Wikipedia

Wikipedia

The logo of Wikipedia, a globe featuring glyphs from many different writing systems
Screenshot Screenshot of Wikipedia's multilingual portal.
Type of site	Internet encyclopedia
Available in	271 active editions (282 in total)
Headquarters	Miami, Florida
Owner	Wikimedia Foundation (non-profit)
Created by	Jimmy Wales, Larry Sanger
URL	wikipedia.org
Commercial	No
Registration	Optional (required only for certain tasks such as editing protected pages, creating pages or uploading files)

Wikipedia (/ˌwɪkˈpiːdiə/ or /ˌwɪkiˈpiːdiə/ WIK-i-PEE-dee-ə) is a free, collaborative, multilingual Internet encyclopedia supported by the non-profit Wikimedia Foundation. Its 20 million articles (over 6.8 million in English alone) have been written collaboratively by volunteers around the world. Almost all of its articles can be edited by anyone with access to the site, and it has about 100,000 regularly active contributors. As of January 2012, there are editions of Wikipedia in 283 languages. It has become the largest and most popular general reference work on the Internet, ranking sixth globally among all websites on Alexa and having an estimated 365 million readers worldwide. It is estimated that Wikipedia receives 2.7 billion monthly pageviews from the United States alone.

Wikipedia was launched in January 2001 by Jimmy Wales and Larry Sanger. Sanger coined the name Wikipedia, which is a portmanteau of wiki (a technology for creating websites collaboratively, from the Hawaiian word wiki, meaning "quick") and encyclopedia.

Wikipedia's departure from the expert-driven style of encyclopedia building and the presence of a large body of unacademic content has received ample attention in print media. In its 2006 Person of the Year article, Time magazine recognized the rapid growth of online collaboration and interaction by millions of people around the world. It cited Wikipedia as an example, in addition to YouTube, MySpace, and Facebook. Wikipedia has also been praised as a news source because of how quickly articles about recent events appear. Students have been assigned to write Wikipedia articles as an exercise in clearly and succinctly explaining difficult concepts to an uninitiated audience.

Although the policies of Wikipedia strongly espouse verifiability and a neutral point of view, critics of Wikipedia accuse it of systemic bias and inconsistencies (including undue weight given to popular culture); and because it favors consensus over credentials in its editorial processes, its reliability and accuracy are also targeted. Other criticisms center on its susceptibility to vandalism and the addition of spurious or unverified information; though some scholarly work suggests that vandalism is generally short-lived. A 2005 investigation in Nature showed that the science articles they compared came close to the level of accuracy of Encyclopædia Britannica and had a similar rate of "serious errors".

History

Main article: History of Wikipedia

Wikipedia originally developed from another encyclopedia project, Nupedia.

Wikipedia began as a complementary project for Nupedia, a free online English-language encyclopedia project whose articles were written by experts and reviewed under a formal process. Nupedia was founded on March 9, 2000, under the ownership of Bomis, Inc, a web portal company. Its main figures were Jimmy Wales, Bomis CEO, and Larry Sanger, editor-in-chief for Nupedia and later Wikipedia. Nupedia was licensed initially under its own Nupedia Open Content License, switching to the GNU Free Documentation License before Wikipedia's founding at the urging of Richard Stallman.

Main Page of the English Wikipedia on October 20, 2010.

Larry Sanger and Jimmy Wales founded Wikipedia. While Wales is credited with defining the goal of making a publicly editable encyclopedia, Sanger is usually credited with the strategy of using a wiki to reach that goal. On January 10, 2001, Sanger proposed on the Nupedia mailing list to create a wiki as a "feeder" project for Nupedia. Wikipedia was formally launched on January 15, 2001, as a single English-language edition at www.wikipedia.com, and announced by Sanger on the Nupedia mailing list. Wikipedia's policy of "neutral point-of-view" was codified in its initial months, and was similar to Nupedia's earlier "nonbiased" policy. Otherwise, there were relatively few rules initially and Wikipedia operated independently of Nupedia.

Number of articles in the English Wikipedia (in blue)

Wikipedia gained early contributors from Nupedia, Slashdot postings, and web search engine indexing. It grew to approximately 20,000 articles and 18 language editions by the end of 2001. By late 2002, it had reached 26 language editions, 46 by the end of 2003, and 161 by the final days of 2004. Nupedia and Wikipedia coexisted until the former's servers were taken down permanently in 2003, and its text was incorporated into Wikipedia. English Wikipedia passed the two million-article mark on September 9, 2007, making it the largest encyclopedia ever assembled, eclipsing even the 1407 Yongle Encyclopedia, which had held the record for exactly 600 years. Citing fears of commercial advertising and lack of control in a perceived English-centric Wikipedia, users of the Spanish Wikipedia forked from Wikipedia to create the Enciclopedia Libre in February 2002. Later that year, Wales announced that Wikipedia would not display advertisements, and its website was moved to wikipedia.org. Various other wiki-encyclopedia projects have been started, largely under a different philosophy from the open and NPOV editorial model of Wikipedia. Wikinfo does not require a neutral point of view and allows original research. New Wikipedia-inspired projects – such as Citizendium, Scholarpedia, Conservapedia, and Google's Knol where the articles are a little more essayistic – have been started to address perceived limitations of Wikipedia, such as its policies on peer review, original research, and commercial advertising.

Growth of the number of articles in the English Wikipedia (in blue)

Though the English Wikipedia reached three million articles in August 2009, the growth of the edition, in terms of the numbers of articles and of contributors, appears to have peaked around early 2007. Around 1,800 articles were added daily to the encyclopaedia in 2006; by 2010 that average was roughly 1,000. A team at the Palo Alto Research Center speculated that this is due to the increasing exclusiveness of the project. Others suggest that the growth is flattening naturally because articles that could be called 'low-hanging fruit' – topics that clearly merit an article – have already been created and built up extensively.

In November 2009, a PhD thesis written by Felipe Ortega, a researcher at the Rey Juan Carlos University in Madrid, found that the English Wikipedia had lost 49,000 editors during the first three months of 2009; in comparison, the project lost only 4,900 editors during the same period in 2008. The Wall Street Journal reported that "unprecedented numbers of the millions of online volunteers who write, edit and police [Wikipedia] are quitting". The array of rules applied to editing and disputes related to such content are among the reasons for this trend that are cited in the article. These claims were disputed by Jimmy Wales, who denied the decline and questioned the methodology of the study.

In January 2007, Wikipedia initially entered the top ten list of the most popular websites in the United States, according to comScore Networks Inc. With 42.9 million unique visitors, Wikipedia was ranked No. 9, surpassing the New York Times (#10) and Apple Inc. (#11). This marked a significant increase over January 2006, when the rank was No. 33, with Wikipedia receiving around 18.3 million unique visitors. In April 2011, Wikipedia was listed as the fifth-most-popular website by Google Inc. As of October 2011, Wikipedia is the sixth-most-popular website worldwide according to Alexa Internet, receiving more than 2.7 billion U.S. pageviews every month, out of a global monthly total of over 12 billion pageviews. In January 2012, the founder of Wikipedia, Jimmy Wales, called for a twenty-four shut down of Wikipedia as a protest against SOPA.

Nature of Wikipedia

See also: Reliability of Wikipedia and Academic studies about Wikipedia

As the popular joke goes, ‘The problem with Wikipedia is that it only works in practice. In theory, it can never work.’

— Miikka Ryokas,

Editing

In April 2009, the Wikimedia Foundation conducted a Wikipedia usability study, questioning users about the editing mechanism.

In a departure from the style of traditional encyclopedias, Wikipedia employs an open, "wiki" editing model. Except for particularly vandalism-prone pages, every article may be edited anonymously or with a user account. Different language editions modify this policy: only registered users may create a new article in the English edition. No article is owned by its creator or any other editor, or is vetted by any recognized authority; rather, the articles are agreed on by consensus.

By default, any edit to an article becomes available immediately, prior to any review. This means that an article may contain errors, misguided contributions, advocacy, or even patent nonsense, until another editor corrects the problem. Different language editions, each under separate administrative control, are free to modify this policy. For example the German Wikipedia maintains a system of "stable versions" of articles, to allow a reader to see versions of articles that have passed certain reviews. In June 2010, the English Wikipedia began a trial of a "pending changes" system where new users' edits to certain "controversial" or vandalism-prone articles (such as George W. Bush, David Cameron or homework) would be "subject to review from an established Wikipedia editor before publication", which, as Jimmy Wales told the BBC, would enable the English Wikipedia "to open up articles for general editing that have been protected or semi-protected for years". Wales opted against the German Wikipedia model of requiring editor review before edits to any article, describing it as "neither necessary nor desirable". The trial lasted until May 2011.

Editors keep track of changes to articles by checking the difference between two revisions of a page, displayed here in red.

Contributors, registered or not, can take advantage of features available in the software that powers Wikipedia. The "History" page attached to each article records every single past revision of the article, though a revision with libelous content, criminal threats or copyright infringements may be removed afterwards. This feature makes it easy to compare old and new versions, undo changes that an editor considers undesirable, or restore lost content. The "Talk" pages associated with each article are used to coordinate work among multiple editors. Regular contributors often maintain a "watchlist" of articles of interest to them, so that they can easily keep tabs on all recent changes to those articles. Computer programs called bots have been used widely to remove vandalism as soon as it was made, to correct common misspellings and stylistic issues, or to start articles such as geography entries in a standard format from statistical data.

The editing interface of Wikipedia.

Articles in Wikipedia are organized roughly in three ways according to: development status, subject matter and the access level required for editing. The most developed state of articles is called "featured article" status: articles labeled as such are the ones that will be featured in the main page of Wikipedia. Researcher Giacomo Poderi found that articles tend to reach the FA status via the intensive work of few editors. In 2007, in preparation for producing a print version, the English-language Wikipedia introduced an assessment scale against which the quality of articles is judged.

A WikiProject is a place for a group of editors to coordinate work on a specific topic. The discussion pages attached to a project are often used to coordinate changes that take place across articles. Wikipedia also maintains a style guide called the Manual of Style (or MoS for short), which stipulates, for example, that, in the first sentence of any given article, the title of the article and any alternative titles should appear in bold.

Defenses against undesirable edits

The open nature of the editing model has been central to most criticism of Wikipedia. For example, a reader of an article cannot be certain that it has not been compromised by the insertion of false information or the removal of essential information. Former Encyclopædia Britannica editor-in-chief Robert McHenry once described this by saying:

The user who visits Wikipedia to learn about some subject, to confirm some matter of fact, is rather in the position of a visitor to a public restroom. It may be obviously dirty, so that he knows to exercise great care, or it may seem fairly clean, so that he may be lulled into a false sense of security. What he certainly does not know is who has used the facilities before him.

John Seigenthaler has described Wikipedia as "a flawed and irresponsible research tool".

However, obvious vandalism is easy to remove from wiki articles, since the previous versions of each article are kept. In practice, the median time to detect and fix vandalisms is very low, usually a few minutes, but in one particularly well-publicized incident, false information was introduced into the biography of American political figure John Seigenthaler and remained undetected for four months. John Seigenthaler, the founding editorial director of USA Today and founder of the Freedom Forum First Amendment Center at Vanderbilt University, called Jimmy Wales and asked if Wales had any way of knowing who contributed the misinformation. Wales replied that he did not, nevertheless the perpetrator was eventually traced. This incident led to policy changes on the site, specifically targeted at tightening up the verifiability of all biographical articles of living people.

Wikipedia's open structure inherently makes it an easy target for Internet trolls, spamming, and those with an agenda to push. The addition of political spin to articles by organizations including members of the US House of Representatives and special interest groups has been noted, and organizations such as Microsoft have offered financial incentives to work on certain articles. These issues have been parodied, notably by Stephen Colbert in The Colbert Report.

For example, in August 2007, the website WikiScanner began to trace the sources of changes made to Wikipedia by anonymous editors without Wikipedia accounts. The program revealed that many such edits were made by corporations or government agencies changing the content of articles related to them, their personnel or their work.

Wikipedia can be defended from attack by several systems and techniques. These include users checking pages and edits (e.g. 'watchlists' and 'recent changes'), computer programs ('bots') that are designed to try to detect attacks and fix them automatically (or semi-automatically), filters that warn users making "undesirable" edits, blocks on the creation of links to particular websites, blocks on edits from particular accounts, IP addresses or address ranges.

For heavily attacked pages, particular articles can be semi-protected so that only well established accounts can edit them, or for particularly contentious cases, locked so that only administrators are able to make changes. Such locking is allegedly applied sparingly and for only short periods of time while attacks may appear likely to continue.

Rules and laws governing content and editor behavior

Content in Wikipedia is subject to the laws (in particular, the copyright laws) of the United States and of the U.S. state of Florida, where the majority of Wikipedia's servers reside. Beyond legal matters, the editorial principles of Wikipedia are embodied in the "five pillars", and numerous policies and guidelines that are intended to shape the content appropriately. Even these rules are stored in wiki form, and Wikipedia editors as a community are able to write and revise the website's policies and guidelines. Rules can be enforced by deleting or modifying article materials failing to meet them. The rules on the non-English editions of Wikipedia branched off a translation of the rules on the English Wikipedia and have since diverged to some extent. While they still show similarities, they differ in many details.

English Wikipedia

Content policies

According to the rules on the English Wikipedia, each entry in Wikipedia to be worthy of inclusion must be about a topic that is encyclopedic and is not a dictionary entry or dictionary-like. A topic should also meet Wikipedia's standards of "notability", which usually means that it must have received significant coverage in reliable secondary sources such as mainstream media or major academic journals that are independent of the subject of the topic. Further, Wikipedia must expose knowledge that is already established and recognized. In other words, it must not present, for instance, new information or original works. A claim that is likely to be challenged requires a reference to a reliable source. Among Wikipedia editors, this is often phrased as "verifiability, not truth" to express the idea that the readers, not the encyclopedia, are ultimately responsible for checking the truthfulness of the articles and making their own interpretations. This can lead to the removal of information that is valid, thus hindering inclusion of knowledge and growth of the encyclopedia. Finally, Wikipedia must not take a side. All opinions and viewpoints, if attributable to external sources, must enjoy an appropriate share of coverage within an article. This is known as neutral point of view (NPOV).

Dispute resolution

Wikipedia has many methods of settling disputes. A "BOLD, revert, discuss" cycle sometimes occurs, in which an editor changes something, another editor reverts that, and then the matter is discussed on the appropriate talk page. In order to gain a broader community consensus, issues can be raised at the Village Pump, or a Request for Comment can be made soliciting other editors' input. "Wikiquette Assistance" is a non-binding noticeboard where editors can report impolite, uncivil, or other difficult communications with other editors. Specialized forums exist for centralizing discussion on specific decisions, such as whether or not an article should be deleted. Mediation is sometimes used, although it has been deemed by some Wikipedians to be unhelpful for resolving particularly contentious disputes.

Arbitration Committee

The Arbitration Committee is the ultimate dispute resolution method. Although disputes usually arise from a disagreement between 2 opposing views on how articles should read, the Arbitration Committee explicitly refuses to directly rule on which view should be adopted. Statistical analyses suggest that the committee ignores the content of disputes and focuses on the way disputes are conducted instead, functioning not so much to resolve disputes and make peace between conflicting editors, but to weed out problematic editors while weeding potentially productive editors back in to participate. Therefore, the committee does not directly decide how content should be, although it sometimes condemns content changes when it deems the new content violates Wikipedia policies (for example, by being biased). Its remedies include cautions and probations (used in 63.2% of cases) and banning editors from articles (43.3%), subject matters (23.4%) or Wikipedia (15.7%). Complete bans from Wikipedia are largely limited to instances of impersonation and anti-social behavior. When conduct is not impersonation or anti-social, but rather anti-consensus or violating editing policies, warnings tend to be issued.

Content licensing

All text in Wikipedia was covered by GNU Free Documentation License (GFDL), a copyleft license permitting the redistribution, creation of derivative works, and commercial use of content while authors retain copyright of their work, up until June 2009, when the site switched to Creative Commons Attribution-ShareAlike (CC BY-SA) 3.0. Wikipedia had been working on the switch to Creative Commons licenses because the GFDL, initially designed for software manuals, was not considered suitable for online reference works and because the two licenses were incompatible. In response to the Wikimedia Foundation's request, in November 2008, the Free Software Foundation (FSF) released a new version of GFDL designed specifically to allow Wikipedia to relicense its content to CC BY-SA by August 1, 2009. Wikipedia and its sister projects held a community-wide referendum to decide whether or not to make the license switch. The referendum took place from April 9 to 30. The results were 75.8% "Yes", 10.5% "No", and 13.7% "No opinion". In consequence of the referendum, the Wikimedia Board of Trustees voted to change to the Creative Commons license, effective June 15, 2009.

The handling of media files (e.g., image files) varies across language editions. Some language editions, such as the English Wikipedia, include non-free image files under fair use doctrine, while the others have opted not to, in part due to the lack of fair use doctrines in their home countries (e.g., in Japanese copyright law). Media files covered by free content licenses (e.g., Creative Commons' CC BY-SA) are shared across language editions via Wikimedia Commons repository, a project operated by the Wikimedia Foundation.

The Wikimedia foundation is not a licensor of content, but merely a hosting service for the contributors (and licensors) of the Wikipedia. This position has been successfully defended in court.

Accessing Wikipedia's content

Because Wikipedia content is distributed under an open license, anyone can reuse, or re-distribute it at no charge. The content of Wikipedia has been published in many forms, both online and offline, outside of the Wikipedia website.

• Web sites – Thousands of "mirror sites" exist that republish content from Wikipedia; two prominent ones, that also include content from other reference sources, are Reference.com and Answers.com. Another example is Wapedia, which began to display Wikipedia content in a mobile-device-friendly format before Wikipedia itself did.
• Mobile apps – A variety of mobile apps provide access to Wikipedia on hand-held devices, including both Android and Apple iOS devices (see Wikipedia iOS apps). (See also Mobile access).
• Search engines – Some web search engines make special use of Wikipedia content when displaying search results: examples include Bing (via technology gained from Powerset) and Duck Duck Go.
• Other wikis – Some wikis, most notably Enciclopedia Libre and Citizendium, began as forks of Wikipedia content. The website DBpedia, begun in 2007, is a project that extracts data from the infoboxes and category declarations of the English-language Wikipedia and makes it available in a queriable semantic format, RDF. The possibility has also been raised to have Wikipedia export its data directly in a semantic format, possibly by using the Semantic MediaWiki extension. Such an export of data could also help Wikipedia reuse its own data, both between articles on the same language Wikipedia and between different language Wikipedias.
• Compact Discs, DVDs – Collections of Wikipedia articles have also been published on optical discs. An English version, 2006 Wikipedia CD Selection, contained about 2,000 articles. The Polish-language version contains nearly 240,000 articles. There are also German and Spanish-language versions. Also: "Wikipedia for Schools", the Wikipedia series of CDs/DVDs, produced by Wikipedians and SOS Children, is a free, hand-checked, non-commercial selection from Wikipedia targeted around the UK National Curriculum and intended to be useful for much of the English-speaking world. The project is available online; an equivalent print encyclopedia would require roughly 20 volumes.
• Books – There has also been an attempt to put a select subset of Wikipedia's articles into printed book form. Since 2009, tens of thousands of print on demand books which reproduced English, German, Russian and French Wikipedia articles have been produced by the American company Books LLC and by three Mauritian subsidiaries of the German publisher VDM.

Wikipedia blackout protest against SOPA on January 18, 2012

Obtaining the full contents of Wikipedia for reuse presents challenges, since direct cloning via a web crawler is discouraged. Wikipedia publishes "dumps" of its contents, but these are text-only; as of 2007 there is no dump available of Wikipedia's images. Wikipedia joined a protest against the US SOPA by blacking out its English-language pages for 24 hours on January 18, 2012. More than 162 million people viewed the blackout explanation page that temporarily replaced Wikipedia content.

Coverage of topics

See also: Notability in English Wikipedia

Pie chart of Wikipedia content by subject as of January 2008

Wikipedia comprises information in a variety of topics, including earthquakes, for example. In the picture, is the article for the 2010 Pichilemu earthquake.

Wikipedia seeks to create a summary of all human knowledge in the form of an online encyclopedia, with each topic of knowledge covered encyclopedically in one article. Since it has virtually unlimited disk space, it can have far more topics than can be covered by any conventional printed encyclopedia. It also contains materials that some people may find objectionable, offensive, or pornographic. It was made clear that this policy is not up for debate, and the policy has sometimes proved controversial. For instance, in 2008, Wikipedia rejected an online petition against the inclusion of Muhammad's depictions in its English edition, citing this policy. The presence of politically, religiously, and pornographically sensitive materials in Wikipedia has led to the censorship of Wikipedia by national authorities in China, Pakistan and the United Kingdom, among other countries.

As of September 2009, Wikipedia articles cover about half a million places on Earth. However, research conducted by the Oxford Internet Institute has shown that the geographic distribution of articles is highly uneven. Most articles are written about North America, Europe, and East Asia, with very little coverage of large parts of the developing world, including most of Africa.

A 2008 study conducted by researchers at Carnegie Mellon University and Palo Alto Research Center gave a distribution of topics as well as growth (from July 2006 to January 2008) in each field:

• Culture and the arts: 30% (210%)
• Biographies and persons: 15% (97%)
• Geography and places: 14% (52%)
• Society and social sciences: 12% (83%)
• History and events: 11% (143%)
• Natural and the physical sciences: 9% (213%)
• Technology and the applied science: 4% (−6%)
• Religions and belief systems: 2% (38%)
• Health: 2% (42%)
• Mathematics and logic: 1% (146%)
• Thought and philosophy: 1% (160%)

These numbers relate only to articles; it is possible that one topic contains a lot of short articles and another one quite large ones. Through its "Wikipedia Loves Libraries" program, Wikipedia has partnered with major public libraries such as the New York Public Library for the Performing Arts to expand its coverage of underrepresented subjects and articles.

Furthermore, the exact coverage of Wikipedia is under constant review by the editors, and disagreements are not uncommon (see also deletionism and inclusionism).

Quality of writing

Because contributors usually rewrite small portions of an entry rather than making full-length revisions, high- and low-quality content may be intermingled within an entry. Critics sometimes argue that non-expert editing undermines quality. For example, Roy Rosenzweig, a history professor, stated that American National Biography Online outperformed Wikipedia in terms of its "clear and engaging prose", which, he said, was an important aspect of good historical writing. Contrasting Wikipedia's treatment of Abraham Lincoln to that of Civil War historian James McPherson in American National Biography Online, he said that both were essentially accurate and covered the major episodes in Lincoln's life, but praised "McPherson's richer contextualization... his artful use of quotations to capture Lincoln's voice ... and ... his ability to convey a profound message in a handful of words." By contrast, he gives an example of Wikipedia's prose that he finds "both verbose and dull". Rosenzweig also criticized the "waffling—encouraged by the npov policy—[which] means that it is hard to discern any overall interpretive stance in Wikipedia history." By example, he quoted the conclusion of Wikipedia's article on William Clarke Quantrill. While generally praising the article, he pointed out its "waffling" conclusion: "Some historians...remember him as an opportunistic, bloodthirsty outlaw, while others continue to view him as a daring soldier and local folk hero."

Other critics have made similar charges that, even if Wikipedia articles are factually accurate, they are often written in a poor, almost unreadable style. Frequent Wikipedia critic Andrew Orlowski commented: "Even when a Wikipedia entry is 100 per cent factually correct, and those facts have been carefully chosen, it all too often reads as if it has been translated from one language to another then into to a third, passing an illiterate translator at each stage." A study of cancer articles by Yaacov Lawrence of the Kimmel Cancer Center at Thomas Jefferson University found that the entries were mostly accurate, but they were written at college reading level, as opposed to the ninth grade level seen in the Physician Data Query. He said that "Wikipedia's lack of readability may reflect its varied origins and haphazard editing." The Economist argued that better-written articles tend to be more reliable: "inelegant or ranting prose usually reflects muddled thoughts and incomplete information." A 2005 study by the journal Nature compared Wikipedia's science content to that of Encyclopædia Britannica, stating that Wikipedia's accuracy was close to that of Britannica, but that the structure of Wikipedia's articles was often poor.

Reliability

Main article: Reliability of Wikipedia

The crowdsourced nature of Wikipedia's content creation means that anyone can add falsehoods to, or vandalize, the site. However, it also enables people to easily correct such mistakes.

As a consequence of the open structure, Wikipedia "makes no guarantee of validity" of its content, since no one is ultimately responsible for any claims appearing in it. Concerns have been raised regarding the lack of accountability that results from users' anonymity, the insertion of spurious information, vandalism, and similar problems.

Wikipedia has often been accused of exhibiting systemic bias and inconsistency; additionally, critics argue that Wikipedia's open nature and a lack of proper sources for most of the information makes it unreliable. Some commentators suggest that Wikipedia may be reliable, but that the reliability of any given article is not clear. Editors of traditional reference works such as the Encyclopædia Britannica have questioned the project's utility and status as an encyclopedia. Most university lecturers discourage students from citing any encyclopedia in academic work, preferring primary sources; some specifically prohibit Wikipedia citations. Co-founder Jimmy Wales stresses that encyclopedias of any type are not usually appropriate to use as citeable sources, and should not be relied upon as authoritative.

A non-scientific report in the journal Nature in 2005 suggested that for some scientific articles Wikipedia came close to the level of accuracy of Encyclopædia Britannica and had a similar rate of "serious errors." These claims have been disputed by, among others, Encyclopædia Britannica.

An economist, Tyler Cowen writes, "If I had to guess whether Wikipedia or the median refereed journal article on economics was more likely to be true, after a not so long think I would opt for Wikipedia." He comments that some traditional sources of non-fiction suffer from systemic biases and novel results, in his opinion, are over-reported in journal articles and relevant information is omitted from news reports. However, he also cautions that errors are frequently found on Internet sites, and that academics and experts must be vigilant in correcting them.

In February 2007 an article in The Harvard Crimson newspaper reported that a few of the professors at Harvard University include Wikipedia in their syllabi, but that there is a split in their perception of using Wikipedia. In June 2007 former president of the American Library Association Michael Gorman condemned Wikipedia, along with Google, stating that academics who endorse the use of Wikipedia are "the intellectual equivalent of a dietitian who recommends a steady diet of Big Macs with everything." He also said that "a generation of intellectual sluggards incapable of moving beyond the Internet" was being produced at universities. He complains that the web-based sources are discouraging students from learning from the more rare texts which are found only on paper or subscription-only web sites. In the same article Jenny Fry (a research fellow at the Oxford Internet Institute) commented on academics who cite Wikipedia, saying that: "You cannot say children are intellectually lazy because they are using the Internet when academics are using search engines in their research. The difference is that they have more experience of being critical about what is retrieved and whether it is authoritative. Children need to be told how to use the Internet in a critical and appropriate way."

A Harvard Law textbook, Legal Research in a Nutshell (2011), cites Wikipedia as a “general source” that “can be a real boon” in “coming up to speed in the law governing a situation” and, “while not authoritative, can provide basic facts as well as leads to more in-depth resources.”

Plagiarism concerns

The Wikipedia Watch criticism website in 2006 has listed dozens of examples of plagiarism by Wikipedia editors on the English version. Jimmy Wales, the Wikipedia co-founder, has said in this respect: "We need to deal with such activities with absolute harshness, no mercy, because this kind of plagiarism is 100% at odds with all of our core principles."

Sexual content

Wikipedia has been criticized for allowing graphic sexual content such as images and videos of masturbation and ejaculation as well as photos from hardcore pornographic films in its articles.

The Wikipedia article about Virgin Killer – a 1976 album from German heavy metal band Scorpions – features a picture of the album's original cover, which depicts a naked prepubescent girl. The original release cover caused controversy and was replaced in some countries. In December 2008, access to the Wikipedia article Virgin Killer was blocked for four days by most Internet service providers in the United Kingdom, after it was reported by a member of the public as child pornography, to the Internet Watch Foundation (IWF) which issues a stop list to ISPs. IWF, a nonprofit, nongovernment-affiliated organization, later criticized the inclusion of the picture as "distasteful."

In April 2010, Larry Sanger wrote a letter to the Federal Bureau of Investigation, outlining his concerns that two categories of images on Wikimedia Commons contained child pornography, and were in violation of U.S. federal obscenity law. Sanger later clarified that the images, which were related to pedophilia and one about lolicon, were not of real children, but said that they constituted "obscene visual representations of the sexual abuse of children", under the PROTECT Act of 2003. That law bans photographic child pornography and cartoon images and drawings of children that are obscene under American law. Sanger also expressed concerns about access to the images on Wikipedia in schools. Wikipedia strongly rejected Sanger's accusation. Wikimedia Foundation spokesman Jay Walsh said that Wikipedia does not have "material we would deem to be illegal. If we did, we would remove it." Following the complaint by Larry Sanger, Wales deleted sexual images without consulting the community. After some editors who volunteer to maintain the site argued that the decision to delete had been made hastily, Wales voluntarily gave up some of the powers he had held up to that time as part of his co-founder status. He wrote in a message to the Wikimedia Foundation mailing list that this action was "in the interest of encouraging this discussion to be about real philosophical/content issues, rather than be about me and how quickly I acted."

Privacy

One privacy concern in the case of Wikipedia is the right of a private citizen to remain private; to remain a "private citizen" rather than a "public figure" in the eyes of the law. It is somewhat of a battle between the right to be anonymous in cyberspace and the right to be anonymous in real life ("meatspace"). Wikipedia Watch argues that "Wikipedia is a potential menace to anyone who values privacy" and that "a greater degree of accountability in the Wikipedia structure" would be "the very first step toward resolving the privacy problem." A particular problem occurs in the case of an individual who is relatively unimportant and for whom there exists a Wikipedia page against their wishes.

In 2005 Agence France-Presse quoted Daniel Brandt, the Wikipedia Watch owner, as saying that "the basic problem is that no one, neither the trustees of Wikimedia Foundation, nor the volunteers who are connected with Wikipedia, consider themselves responsible for the content."

In January 2006, a German court ordered the German Wikipedia shut down within Germany because it stated the full name of Boris Floricic, aka "Tron", a deceased hacker who was formerly with the Chaos Computer Club. More specifically, the court ordered that the URL within the German .de domain (http://www.wikipedia.de/) may no longer redirect to the encyclopedia's servers in Florida at http://de.wikipedia.org although German readers were still able to use the US-based URL directly, and there was virtually no loss of access on their part. The court order arose out of a lawsuit filed by Floricic's parents, demanding that their son's surname be removed from Wikipedia. On February 9, 2006, the injunction against Wikimedia Deutschland was overturned, with the court rejecting the notion that Tron's right to privacy or that of his parents were being violated. The plaintiffs appealed to the Berlin state court, but were refused in May 2006.

Community

Main article: Community of Wikipedia

Wikimania, an annual conference for users of Wikipedia and other projects operated by the Wikimedia Foundation.

Wikipedia's community has been described as "cult-like," although not always with entirely negative connotations, and criticized for failing to accommodate inexperienced users.

Power structure

The Wikipedia community has established "a bureaucracy of sorts", including "a clear power structure that gives volunteer administrators the authority to exercise editorial control." Editors in good standing in the community can run for one of many levels of volunteer stewardship; this begins with "administrator," a group of privileged users who have the ability to delete pages, lock articles from being changed in case of vandalism or editorial disputes, and block users from editing. Despite the name, administrators do not enjoy any special privilege in decision-making; instead they are mostly limited to making edits that have project-wide effects and thus are disallowed to ordinary editors, and to block users making disruptive edits (such as vandalism).

Contributors

Demographics of Wikipedia editors.

Wikipedia does not require that its users provide identification. However, as Wikipedia grows with its unconventional model of encyclopedia building, "Who writes Wikipedia?" has become one of the questions frequently asked on the project, often with a reference to other Web 2.0 projects such as Digg. Jimmy Wales once argued that only "a community ... a dedicated group of a few hundred volunteers" makes the bulk of contributions to Wikipedia and that the project is therefore "much like any traditional organization." Wales performed a study finding that over 50% of all the edits are done by just 0.7% of the users (at the time: 524 people). This method of evaluating contributions was later disputed by Aaron Swartz, who noted that several articles he sampled had large portions of their content (measured by number of characters) contributed by users with low edit counts. A 2007 study by researchers from Dartmouth College found that "anonymous and infrequent contributors to Wikipedia ... are as reliable a source of knowledge as those contributors who register with the site." Although some contributors are authorities in their field, Wikipedia requires that even their contributions be supported by published and verifiable sources. The project's preference for consensus over credentials has been labeled "anti-elitism."

In a 2003 study of Wikipedia as a community, economics PhD student Andrea Ciffolilli argued that the low transaction costs of participating in wiki software create a catalyst for collaborative development, and that a "creative construction" approach encourages participation. In his 2008 book, The Future of the Internet and How to Stop It, Jonathan Zittrain of the Oxford Internet Institute and Harvard Law School’s Berkman Center for Internet & Society cites Wikipedia's success as a case study in how open collaboration has fostered innovation on the web. A 2008 study found that Wikipedia users were less agreeable and open, though more conscientious, than non-Wikipedia users. A 2009 study suggested there was "evidence of growing resistance from the Wikipedia community to new content."

At OOPSLA 2009, Wikimedia CTO and Senior Software Architect Brion Vibber gave a presentation entitled "Community Performance Optimization: Making Your People Run as Smoothly as Your Site" in which he discussed the challenges of handling the contributions from a large community and compared the process to that of software development.

Interactions

Wikipedians and British Museum curators collaborate on the article Hoxne Hoard in June 2010.

Members of the community predominantly interact with each other via 'talk' pages, which are wiki-edited pages which are associated with articles, as well as via talk pages that are specific to particular contributors, and talk pages that help run the site. These pages help the contributors reach consensus about what the contents of the articles should be, how the site's rules may change, and to take actions with respect to any problems within the community.

The Wikipedia Signpost is the community newspaper on the English Wikipedia, and was founded by Michael Snow, an administrator and the former chair of the Wikimedia Foundation board of trustees. It covers news and events from the site, as well as major events from sister projects, such as Wikimedia Commons.

Positive re-inforcement

Wikipedians sometimes award one another barnstars for good work. These personalized tokens of appreciation reveal a wide range of valued work extending far beyond simple editing to include social support, administrative actions, and types of articulation work. The barnstar phenomenon has been analyzed by researchers seeking to determine what implications it might have for other communities engaged in large-scale collaborations.

New users

60% of registered users never make another edit after their first 24 hours. Possible explanations are that such users only register for a single purpose, or are scared away by their experiences. Goldman writes that editors who fail to comply with Wikipedia cultural rituals, such as signing talk pages, implicitly signal that they are Wikipedia outsiders, increasing the odds that Wikipedia insiders will target their contributions as a threat. Becoming a Wikipedia insider involves non-trivial costs; the contributor is expected to build a user page, learn Wikipedia-specific technological codes, submit to an arcane dispute resolution process, and learn a "baffling culture rich with in-jokes and insider references." Non-logged-in users are in some sense second-class citizens on Wikipedia, as "participants are accredited by members of the wiki community, who have a vested interest in preserving the quality of the work product, on the basis of their ongoing participation," but the contribution histories of IP addresses cannot necessarily with any certainty be credited to, or blamed upon, a particular user.

A 2009 study by Henry Blodget showed that in a random sample of articles most content in Wikipedia (measured by the amount of contributed text which survives to the latest sampled edit) is created by "outsiders" (users with low edit counts), whilst most editing and formatting is done by "insiders" (a select group of established users).

Demographics

The New York Times ran a column about a Wikipedia survey at the time of Wikipedia's 10th anniversary. Quoting from it, "Wikimedia Foundation...collaborated on a study of Wikipedia’s contributor base and discovered that it was barely 13% women; the average age of a contributor was in the mid-20s, according to the study by a joint center of the United Nations University and Maastricht University" and also notes that "surveys suggest that less than 15 percent of its hundreds of thousands of contributors are women." A goal set by Sue Gardner, Wikimedia Foundation Executive Director, is to see female editing contributions increase to 25% by 2015. Linda Basch, President of the National Council for Research on Women notes the contrast in these Wikipedia editors' statistics with the majority percentage which women are currently filling in enrollment in BA, Masters and PhD programs in nations such as the US.

Estimation of contributions shares from different regions in the word to different Wikipedia editions.

In a research article published in PLoS ONE in 2012, Yasseri et al. based on the circadian patterns of editorial activities of the community, have estimated the share of contributions to different edition of Wikipedia from different region of the world. For instance, it has been reported that edits from North America are limited to almost 50% in the English Wikipedia and this value decreases to 25% in Simple English Wikipedia. The article also covers some other editions in different languages.

Language editions

See also: List of Wikipedias

Percentage of all Wikipedia articles in English (red) and top ten largest language editions (blue). As of July 2007 less than 23% of Wikipedia articles are in English.

There are currently 283 language editions (or language versions) of Wikipedia; of these, 4 have over 1 million articles each (English, German, French and Dutch), 6 more have over 700,000 articles (Italian, Polish, Spanish, Russian, Japanese and Portuguese), 40 more have over 100,000 articles and 109 have over 10,000 articles. The largest, the English Wikipedia, has over 6.8 million articles. According to Alexa, the English subdomain (en.wikipedia.org; English Wikipedia) receives approximately 54% of Wikipedia's cumulative traffic, with the remaining split among the other languages (Japanese: 10%, German: 8%, Spanish: 5%, Russian: 4%, French: 4%, Italian: 3%). As of January 2012, the five largest language editions are (in order of article count) English, German, French, Dutch, and Italian Wikipedias.

Since Wikipedia is web-based and therefore worldwide, contributors of a same language edition may use different dialects or may come from different countries (as is the case for the English edition). These differences may lead to some conflicts over spelling differences, (e.g. color vs. colour) or points of view. Though the various language editions are held to global policies such as "neutral point of view," they diverge on some points of policy and practice, most notably on whether images that are not licensed freely may be used under a claim of fair use.

Jimmy Wales has described Wikipedia as "an effort to create and distribute a free encyclopedia of the highest possible quality to every single person on the planet in their own language." Though each language edition functions more or less independently, some efforts are made to supervise them all. They are coordinated in part by Meta-Wiki, the Wikimedia Foundation's wiki devoted to maintaining all of its projects (Wikipedia and others). For instance, Meta-Wiki provides important statistics on all language editions of Wikipedia, and it maintains a list of articles every Wikipedia should have. The list concerns basic content by subject: biography, history, geography, society, culture, science, technology, foodstuffs, and mathematics. As for the rest, it is not rare for articles strongly related to a particular language not to have counterparts in another edition. For example, articles about small towns in the United States might only be available in English, even when they meet notability criteria of other language Wikipedia projects.

Translated articles represent only a small portion of articles in most editions, in part because fully automated translation of articles is disallowed. Articles available in more than one language may offer "Interwiki links", which link to the counterpart articles in other editions.

Operation

Wikimedia Foundation and the Wikimedia chapters

Wikimedia Foundation logo

Main article: Wikimedia Foundation

Wikipedia is hosted and funded by the Wikimedia Foundation, a non-profit organization which also operates Wikipedia-related projects such as Wiktionary and Wikibooks. The Wikimedia chapters, local associations of users and supporters of the Wikimedia projects, also participate in the promotion, the development, and the funding of the project.

Software and hardware

See also: MediaWiki

The operation of Wikipedia depends on MediaWiki, a custom-made, free and open source wiki software platform written in PHP and built upon the MySQL database. The software incorporates programming features such as a macro language, variables, a transclusion system for templates, and URL redirection. MediaWiki is licensed under the GNU General Public License and it is used by all Wikimedia projects, as well as many other wiki projects. Originally, Wikipedia ran on UseModWiki written in Perl by Clifford Adams (Phase I), which initially required CamelCase for article hyperlinks; the present double bracket style was incorporated later. Starting in January 2002 (Phase II), Wikipedia began running on a PHP wiki engine with a MySQL database; this software was custom-made for Wikipedia by Magnus Manske. The Phase II software was repeatedly modified to accommodate the exponentially increasing demand. In July 2002 (Phase III), Wikipedia shifted to the third-generation software, MediaWiki, originally written by Lee Daniel Crocker. Several MediaWiki extensions are installed to extend the functionality of MediaWiki software. In April 2005 a Lucene extension was added to MediaWiki's built-in search and Wikipedia switched from MySQL to Lucene for searching. Currently Lucene Search 2.1, which is written in Java and based on Lucene library 2.3, is used.

Overview of system architecture, December 2010. See server layout diagrams on Meta-Wiki.

Wikipedia currently runs on dedicated clusters of Linux servers (mainly Ubuntu), with a few OpenSolaris machines for ZFS. As of December 2009, there were 300 in Florida and 44 in Amsterdam. Wikipedia employed a single server until 2004, when the server setup was expanded into a distributed multitier architecture. In January 2005, the project ran on 39 dedicated servers in Florida. This configuration included a single master database server running MySQL, multiple slave database servers, 21 web servers running the Apache HTTP Server, and seven Squid cache servers.

Wikipedia receives between 25,000 and 60,000 page requests per second, depending on time of day. Page requests are first passed to a front-end layer of Squid caching servers. Further statistics are available based on a publicly available 3-months Wikipedia access trace. Requests that cannot be served from the Squid cache are sent to load-balancing servers running the Linux Virtual Server software, which in turn pass the request to one of the Apache web servers for page rendering from the database. The web servers deliver pages as requested, performing page rendering for all the language editions of Wikipedia. To increase speed further, rendered pages are cached in a distributed memory cache until invalidated, allowing page rendering to be skipped entirely for most common page accesses.

Mobile access

See also: Wikipedia:Metadata

Wikipedia's original medium was for users to read and edit content using any standard web browser through a fixed internet connection. However, Wikipedia content is now also accessible through the mobile web.

Access to Wikipedia from mobile phones was possible as early as 2004, through the Wireless Application Protocol (WAP), via the Wapedia service. In June 2007 Wikipedia launched en.mobile.wikipedia.org, an official website for wireless devices. In 2009 a newer mobile service was officially released, located at en.m.wikipedia.org, which caters to more advanced mobile devices such as the iPhone, Android-based devices, or the Palm Pre. Several other methods of mobile access to Wikipedia have emerged. Many devices and applications optimise or enhance the display of Wikipedia content for mobile devices, while some also incorporate additional features such as use of Wikipedia metadata (See Wikipedia:Metadata), such as geoinformation.

Impact

Impact on publishing

Some observers have stated that Wikipedia represents an economic threat to publishers of traditional encyclopedias, who may be unable to compete with a product that is essentially free. Nicholas Carr, wrote a 2005 essay, "The amorality of Web 2.0", that criticized websites with user-generated content, like Wikipedia, for possibly leading to professional (and, in his view, superior) content producers going out of business, because "free trumps quality all the time." Carr wrote, "Implicit in the ecstatic visions of Web 2.0 is the hegemony of the amateur. I for one can't imagine anything more frightening." Others dispute the notion that Wikipedia, or similar efforts, will entirely displace traditional publications. For instance, Chris Anderson, the editor-in-chief of Wired Magazine, wrote in Nature that the "wisdom of crowds" approach of Wikipedia will not displace top scientific journals, with their rigorous peer review process.

Cultural significance

Main article: Wikipedia in culture

Graph showing the number of days between every 10,000,000th edit.

In addition to logistic growth in the number of its articles, Wikipedia has steadily gained status as a general reference website since its inception in 2001. According to Alexa and comScore, Wikipedia is among the ten most visited websites worldwide. The growth of Wikipedia has been fueled by its dominant position in Google search results; about 50% of search engine traffic to Wikipedia comes from Google, a good portion of which is related to academic research. The number of readers of Wikipedia worldwide reached 365 million at the end of 2009. The Pew Internet and American Life project found that one third of US Internet users consulted Wikipedia. In October 2006, the site was estimated to have a hypothetical market value of $580 million if it ran advertisements.

Wikipedia's content has also been used in academic studies, books, conferences, and court cases. The Parliament of Canada's website refers to Wikipedia's article on same-sex marriage in the "related links" section of its "further reading" list for the Civil Marriage Act. The encyclopedia's assertions are increasingly used as a source by organizations such as the U.S. Federal Courts and the World Intellectual Property Organization – though mainly for supporting information rather than information decisive to a case. Content appearing on Wikipedia has also been cited as a source and referenced in some U.S. intelligence agency reports. In December 2008, the scientific journal RNA Biology launched a new section for descriptions of families of RNA molecules and requires authors who contribute to the section to also submit a draft article on the RNA family for publication in Wikipedia.

Wikipedia has also been used as a source in journalism, often without attribution, and several reporters have been dismissed for plagiarizing from Wikipedia. In July 2007 Wikipedia was the focus of a 30-minute documentary on BBC Radio 4 which argued that, with increased usage and awareness, the number of references to Wikipedia in popular culture is such that the term is one of a select band of 21st-century nouns that are so familiar (Google, Facebook, YouTube) that they no longer need explanation and are on a par with such 20th-century terms as Hoovering or Coca-Cola.

On September 28, 2007 Italian politician Franco Grillini raised a parliamentary question with the Minister of Cultural Resources and Activities about the necessity of freedom of panorama. He said that the lack of such freedom forced Wikipedia, "the seventh most consulted website" to forbid all images of modern Italian buildings and art, and claimed this was hugely damaging to tourist revenues.

Jimmy Wales receiving the Quadriga A Mission of Enlightenment award.

On September 16, 2007 The Washington Post reported that Wikipedia had become a focal point in the 2008 U.S. election campaign, saying, "Type a candidate's name into Google, and among the first results is a Wikipedia page, making those entries arguably as important as any ad in defining a candidate. Already, the presidential entries are being edited, dissected and debated countless times each day." An October 2007 Reuters article, titled "Wikipedia page the latest status symbol," reported the recent phenomenon of how having a Wikipedia article vindicates one's notability.

Awards

Wikipedia won two major awards in May 2004. The first was a Golden Nica for Digital Communities of the annual Prix Ars Electronica contest; this came with a €10,000 (£6,588; $12,700) grant and an invitation to present at the PAE Cyberarts Festival in Austria later that year. The second was a Judges' Webby Award for the "community" category. Wikipedia was also nominated for a "Best Practices" Webby. On January 26, 2007 Wikipedia was also awarded the fourth highest brand ranking by the readers of brandchannel.com, receiving 15% of the votes in answer to the question "Which brand had the most impact on our lives in 2006?"

In September 2008, Wikipedia received Quadriga A Mission of Enlightenment award of Werkstatt Deutschland along with Boris Tadić, Eckart Höfling, and Peter Gabriel. The award was presented to Jimmy Wales by David Weinberger.

Satire

Wikipedia shown in "Weird Al" Yankovic's music video for his song "White & Nerdy."

Many parody Wikipedia's openness and susceptibility to inserted inaccuracies, with characters vandalizing or modifying the online encyclopedia project's articles.

Comedian Stephen Colbert has parodied or referenced Wikipedia on numerous episodes of his show The Colbert Report and coined the related term wikiality, meaning "together we can create a reality that we all agree on—the reality we just agreed on." Another example can be found in a front-page article in The Onion in July 2006, with the title "Wikipedia Celebrates 750 Years of American Independence." Others draw upon Wikipedia's motto, such as in "The Negotiation," an episode of The Office, where character Michael Scott says "Wikipedia is the best thing ever. Anyone in the world can write anything they want about any subject, so you know you are getting the best possible information." "My Number One Doctor", a 2007 episode of the TV show Scrubs, played on the perception that Wikipedia is an unserious reference tool with a scene in which Dr. Perry Cox reacts to a patient who says that a Wikipedia article indicates that the raw food diet reverses the effects of bone cancer by retorting that the same editor who wrote that article also wrote the Battlestar Galactica episode guide. In one episode of 30 Rock, Pete and Frank add nonsensical information to the Janis Joplin Wikipedia page after telling Jenna that she should look it up to learn more about her, as, since Wikipedia could be edited by anybody, it was the most informative research because they find out more every day.

In 2008, the comedic website CollegeHumor produced a video sketch named "Professor Wikipedia", in which the fictitious Professor Wikipedia instructs a class with a medley of unverifiable and occasionally absurd statements. In July 2009, BBC Radio 4 broadcast a comedy series called Bigipedia, which was set on a website which was a parody of Wikipedia. Some of the sketches were directly inspired by Wikipedia and its articles.

Related projects

A number of interactive multimedia encyclopedias incorporating entries written by the public existed long before Wikipedia was founded. The first of these was the 1986 BBC Domesday Project, which included text (entered on BBC Micro computers) and photographs from over 1 million contributors in the UK, and covering the geography, art, and culture of the UK. This was the first interactive multimedia encyclopedia (and was also the first major multimedia document connected through internal links), with the majority of articles being accessible through an interactive map of the UK. The user-interface and part of the content of the Domesday Project were emulated on a website until 2008. One of the most successful early online encyclopedias incorporating entries by the public was h2g2, which was created by Douglas Adams and is run by the BBC. The h2g2 encyclopedia was relatively light-hearted, focusing on articles which were both witty and informative. Both of these projects had similarities with Wikipedia, but neither gave full editorial privileges to public users. A similar non-wiki project, the GNUPedia project, co-existed with Nupedia early in its history; however, it has been retired and its creator, free software figure Richard Stallman, has lent his support to Wikipedia.

Wikipedia has also spawned several sister projects, which are also run by the Wikimedia Foundation. The first, "In Memoriam: September 11 Wiki," created in October 2002, detailed the September 11 attacks; this project was closed in October 2006. Wiktionary, a dictionary project, was launched in December 2002; Wikiquote, a collection of quotations, a week after Wikimedia launched, and Wikibooks, a collection of collaboratively written free textbooks and annotated texts. Wikimedia has since started a number of other projects, including Wikimedia Commons, a site devoted to free-knowledge multimedia; Wikinews, for citizen journalism; and Wikiversity, a project for the creation of free learning materials and the provision of online learning activities. Of these, only Commons has had success comparable to that of Wikipedia.

Several languages of Wikipedia also maintain a reference desk, where volunteers answer questions from the general public. According to a study by Pnina Shachaf in the Journal of Documentation, the quality of the Wikipedia reference desk is comparable to a standard library reference desk, with an accuracy of 55%.

Other websites centered on collaborative knowledge base development have drawn inspiration from or inspired Wikipedia. Some, such as Susning.nu, Enciclopedia Libre, Hudong, and Baidu Baike likewise employ no formal review process, whereas others use more traditional peer review, such as Encyclopedia of Life, Stanford Encyclopedia of Philosophy, Scholarpedia, h2g2, and Everything2. The online wiki-based encyclopedia Citizendium was started by Wikipedia co-founder Larry Sanger in an attempt to create an "expert-friendly" Wikipedia.

A number of published biological databases now use wikis.

See also

• Bibliography of Wikipedia
• Democratization of knowledge
• Interpedia, an early proposal for a collaborative Internet encyclopedia
• List of online encyclopedias
• List of wikis
• Network effect
• QRpedia – multilingual, mobile interface to Wikipedia
• US Congressional staff edits to Wikipedia
• User-generated content
• Wikipedia in culture
• Wikipedia Review

Special searches

• All pages with titles containing Wikipedia
• All pages with titles beginning with Wikipedia

Further reading

Academic studies

Main article: Academic studies about Wikipedia

• Yasseri, Taha (2012). Szolnoki, Attila (ed.). "Circadian Patterns of Wikipedia Editorial Activity: A Demographic Analysis". PLoS ONE. 7 (1): e30091. doi:10.1371/journal.pone.0030091. PMC 3260192. PMID 22272279. {{cite journal}}: Unknown parameter |coauthor= ignored (|author= suggested) (help)CS1 maint: unflagged free DOI (link)
• Goldman, Eric (2010). "Wikipedia's Labor Squeeze and its Consequences". Journal of Telecommunications and High Technology Law. 8. (a blog post by the author)
• Nielsen, Finn (2007). "Scientific Citations in Wikipedia". First Monday. 12 (8). Retrieved February 22, 2008. {{cite journal}}: Unknown parameter |month= ignored (help)
• Pfeil, Ulrike (2006). "Cultural Differences in Collaborative Authoring of Wikipedia". Journal of Computer-Mediated Communication. 12 (1): 88. doi:10.1111/j.1083-6101.2006.00316.x. Retrieved December 26, 2008. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |unused_data= ignored (help)
• Priedhorsky, Reid, Jilin Chen, Shyong (Tony) K. Lam, Katherine Panciera, Loren Terveen, and John Riedl. "Creating, Destroying, and Restoring Value in Wikipedia". Proc. GROUP 2007, doi: 1316624.131663.
• Reagle, Joseph (2007). "Do as I Do: Authorial Leadership in Wikipedia" (PDF). WikiSym '07: Proceedings of the 2007 International Symposium on Wikis. Montreal, Canada: ACM. Retrieved December 26, 2008. {{cite conference}}: Unknown parameter |booktitle= ignored (|book-title= suggested) (help)
• Rosenzweig, Roy. Can History be Open Source? Wikipedia and the Future of the Past. (Originally published in Journal of American History 93.1 (June 2006): 117–46.)
• Wilkinson, Dennis M. (2007). "Assessing the Value of Cooperation in Wikipedia". First Monday. 12 (4). Retrieved February 22, 2008. {{cite journal}}: Unknown parameter |coauthor= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)

Books

• Ayers, Phoebe; Matthews, Charles; Yates, Ben (2008). How Wikipedia Works: And How You Can Be a Part of It. San Francisco: No Starch Press. ISBN 978-1-59327-176-3. {{cite book}}: |access-date= requires |url= (help); Unknown parameter |month= ignored (help)
• Broughton, John (2008). Wikipedia – The Missing Manual. O'Reilly Media. ISBN 0-596-51516-2. {{cite book}}: |access-date= requires |url= (help) (See book rev. by Baker, as listed below.)
• Broughton, John (2008). Wikipedia Reader's Guide. Sebastopol: Pogue Press. ISBN 059652174X.
• Dalby, Andrew (2009). The World and Wikipedia: How We are Editing Reality. Siduri. ISBN 978-0956205209.
• Keen, Andrew (2007). The Cult of the Amateur. Doubleday/Currency. ISBN 978-0-385-52080-5. (substantial criticisms of Wikipedia and other web 2.0 projects). Listen to: Keen, Andrew (June 16, 2007). "Does the Internet Undermine Culture?". Npr.org. Retrieved March 31, 2010. the NPR interview with A. Keen, Weekend Edition Saturday, June 16, 2007.
• Lih, Andrew (2009). The Wikipedia Revolution: How a Bunch of Nobodies Created the World's Greatest Encyclopedia. New York: Hyperion. ISBN 978-1-4013-0371-6.
• O'Sullivan, Dan (September 24, 2009). Wikipedia: a new community of practice?. Ashgate Publishing, Ltd. ISBN 978-0-7546-7433-7. Retrieved October 11, 2011.
• Rafaeli, Sheizaf & Yaron Ariel (2008). "Online motivational factors: Incentives for participation and contribution in Wikipedia." In Barak, A. Psychological aspects of cyberspace: Theory, research, applications. Cambridge, UK: Cambridge University Press. pp. 243–267.
• Reagle, Joseph Michael Jr. (2010). Good Faith Collaboration: The Culture of Wikipedia. Cambridge, MA: The MIT Press. ISBN 978-0-262-01447-2.

Book reviews and other articles

• Baker, Nicholson. "The Charms of Wikipedia". The New York Review of Books, March 20, 2008. Accessed December 17, 2008. (Book rev. of The Missing Manual, by John Broughton, as listed above.)
• Crovitz, L. Gordon. "Wikipedia's Old-Fashioned Revolution: The online encyclopedia is fast becoming the best." (Originally published in Wall Street Journal online – April 6, 2009)

Learning resources

• Wikiversity list of learning resources. (Includes related courses, Web-based seminars, slides, lecture notes, text books, quizzes, glossaries, etc.)

Other media coverage

• Balke, Jeff (2008-03). "For Music Fans: Wikipedia; MySpace". Houston Chronicle (Blog). Retrieved December 17, 2008. {{cite news}}: Check date values in: |date= (help)
• Dee, Jonathan (July 1, 2007). "All the News That's Fit to Print Out". The New York Times Magazine. The New York Times Company. Retrieved February 22, 2008.
• Giles, Jim (September 20, 2007). "Wikipedia 2.0 – Now with Added Trust". New Scientist. Retrieved January 14, 2008.
• Miliard, Mike (December 2, 2007). "Wikipedia Rules". The Phoenix. Retrieved February 22, 2008.
• Poe, Marshall (2006-09). "The Hive". The Atlantic Monthly. Retrieved March 22, 2008. {{cite news}}: Check date values in: |date= (help)
• Rosenwald, Michael S. (October 23, 2009). "Gatekeeper of D.C.'s entry: Road to city's Wikipedia page goes through a DuPont Circle bedroom". The Washington Post. Retrieved October 22, 2009.
• Runciman, David (May 28, 2009). "Like Boiling a Frog". London Review of Books. Retrieved June 3, 2009.
• Taylor, Chris (May 29, 2005). "It's a Wiki, Wiki World". Time. Time, Inc. Retrieved February 22, 2008.
• "Technological Quarterly: Brain Scan: The Free-knowledge Fundamentalist". The Economist Web and Print. June 5, 2008. Retrieved June 5, 2008. Jimmy Wales changed the world with Wikipedia, the hugely popular online encyclopedia that anyone can edit. What will he do next? [leader].
• Is Wikipedia Cracking Up?, The Independent, February 3, 2009

External links

• Wikipedia – multilingual portal (contains links to all language editions of the project)
• Wikipedia mobile phone portal
• Wikipedia at Curlie
• Wikipedia collected news and commentary at The Guardian
• Wikipedia topic page at The New York Times
• Video of TED Talk by Jimmy Wales on the birth of Wikipedia
• Audio of interview with Jimmy Wales about Wikipedia in general on the EconTalk podcast
• Wikipedia and why it matters – Larry Sanger's 2002 talk at Stanford University. video archive and transcript of the talk
• 10 Wikipedia
• "Intelligence in Wikipedia" Google TechTalk on YouTube, describing an intelligence project utilizing Wikipedia, and how Wikipedia articles could be auto-generated from web content

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