The Other Wiki. The wiki that most people are familiar with. The one that isn't us.
Wikipedia is the most famous wiki out there, and is mostly responsible for inspiring the creation of other wikis (although it was not the first). It presents its information as an encyclopedia and focuses mainly on real-life information.
Given Wikipedia's role as a central information source, you can probably gain more info on the "what" of (for example) Star Wars or Star Trek from it than you can from actually watching the show, and that's nice. Here?
Here, you can get a glimmering of why the show is like that.
Here at TV Tropes, we only care about how things apply to fiction. Don't just tell us the facts; tell us the memes, tell us the archetypes, tell us the catchy ideas and symbolic roles that get planted in people's heads. Got the kernel of an idea bouncing about your head? Throw it down here and see what grows. If we're lucky, our neologism for it will catch on.
... Where were we? Oh yeah.
Wikipedia also has an entry on us. It also lists us in its directory of alternatives, encouraging people to record their trope knowledge here, instead of there. See the We Are Not Alone Index for tropes that have Wikipedia articles.
If you have trouble hopping between the markup on Wikipedia and the markup here, then you're a Wikipedia Syntaxer!