2GET (hopefully)

I think most of the popular forums, 2ch a notable exception, have some draw (usually, only distantly related to the forums themselves) that sucks new people in, after which they stay for the community. Megatokyo Forums, for instance. Most of the regulars (outside of "Story Discussions") no longer care for the webcomic attached, and some openly hate it.

Go-Gaia's avatar system is sorta related to this. IGN has game previews and walkthroughs and stuff. Does PaintBallNation have equipment reviews or anything like that? SA has articles, Weekend Web, Photoshop Phriday and a lot of other content.

Even 4-ch and world4ch have a 'draw' in the attached imageboards. I don't know how popular they would have been without it. I was never on the old world2ch, but my impression is that it was a rather desolate place...