Gift economy
A gift economy is an economic system in which participants give away things of value to the shared benefit of the community.
Gift economies were first formally recognized in the potlatch rituals of Native American societies in the Pacific Northwest. Leaders would give away large amounts of perishable goods to their followers.
The Western scientific tradition is an example of a gift economy. A scientist produces research papers and gives them away to other scientists, through journals and conferences. The other scientists are free to refer to the first scientist's papers. The more citations the scientist has, the more prestige and respect he has, which can attract funding and positions. All of the scientists benefit by an increased pool of knowledge.
The open source software community is an example of a gift economy. Programmers make their source code available to the programming community. Individual programmers gain prestige and respect, and the community as a whole benefits from better software.
Gift economies can co-exist with command economies and market economies.