I never felt I could take to the bank what I was reading on wikipedia. It's hard to trust authors you don't know.
Scholarpedia uses the same idea as wikipedia but is updated by experts in the given field rather than "regular Joes" like me. "Regular Joes" can still modify the content of the website (just like in wikipedia) but it must first be approved by an expert prior to being published.
At least that's how they advertise themselves. Have a look here:
http://www.scholarpedia.org