There is an academic word for the kind of thing that happens on WikiWikiWeb type sites: PeerProduction. The main idea is that instead of having formal relationships in which one person is a writer, another is an editor, another is a reviewer, etc., everybody just pitches in according to their own desires and whims, and content emerges over time. It would be nice to use this page to collect a list of interesting studies about PeerProduction. A related page is PeerProductionCommunities.