General Reference

Description from Tech Radar
Even though printing out the whole of Wikipedia would result in a stack of paper about a kilometre high, it is somewhat exclusive in what it contains. If you're after outrageously detailed guides to popular culture, Wikia's various sub-sites will suck you in and never spit you back out. Take a look at Wookieepedia, the Star Wars wiki, for a perfect example: it features a whopping 70,000 articles, and all of them are obsessively maintained.

A massive online encyclopedia that anyone can update and edit.