I think it's just a nice bonus feature for some of us. Sometimes I need fantasy football advice, sometimes I see a conversation started about football, or music, or whatever and it's fun to just hop in. It certainly adds to the sense of community. Why some posters use it almost exclusively is something I can't speak to.
As far as past posts go, as long as there is a way to archive and link to threads in the past I'm cool with it. Some concerns expressed over post counts make sense as they are a status symbol. Is there a way to transfer the post counts for users over without the posts?
Frankly, as long as the site stays as visually clean as it is now, I don't care about much else.