Terrible model if you trying to generate posts and replies. I visit ONE site like that....very old school site with a very niche/narrow readership.
I almost always chat or PM the OP rather than post.
I good idea is to have a gameday live chat for big events....A few sites i visit use this very well.
I, for one, would come here to just "hang out" and "shoot the shit" while "watching a game" with these guys. I'm sure dozens agree.
So at that point you're basically hosting a chat room full of gamblers. So what? That's a good thing for advertisers, right? If that room gets traffic, then those banners get clicks, and the advertising revenue comes in.
I don't get the problem.