Wikipedia gets a worse rap than it really deserves.

If you ignore most of the pedantic self-important editors/trolls on WP, it's actually a great experience to contribute. I write a lot of articles on Canadian/British law and history, and the WPProjects are very supportive and generally polite. Otherwise, I don't really need to interact with anybody. I simply enjoy contributing to the organization of human knowledge. Nearly a decade and thousands of edits (on various accounts for reasons of anonymity) later, I have yet to have a real negative experience that has affected me in one way or another.