This is actually a pretty interesting question for a thread. Me, I came for the comfy atmosphere, and I stayed for the wonderful people.
As for the concept of a forum itself, I love the fact that discussions can span days or even weeks, and that almost every topic can be resurrected provided you have something interesting to say. This is a huge boon to busy people like me; especially those who work alone, and don't often get to talk face-to-face with people.
Oh, and it's nice to talk to people about anime.
