I am a big supporter of the sharing of knowledge and information. Thus I'm thrilled to tell you that you can create you own wiki on any topic or category that you want on Wikia. It is also a great way to find and collaborate with people that love what you love.
Some of the existing wikis are
Wookieepedia(the starwars wiki)
Brickipedia (for lego)
Marvel Comics Wiki (Awesome!)
Harry Potter Wiki (Gay)
and The Twilight Saga Wiki (Really?) now also know as http://vampiresdonotsparkle.tk/
Power to the people, keep on sharing that knowledge.