From experience I've found that sites with moderators who prefer to quash opinion that differs from their own, and thereby reducing variations in opinion, always die. Why? Because it forces the forums to all follow the same line of "we like everything and you can't disagree", which is boring and therefore the people slowly start to drift away as interesting conversation isn't allowed to happen.
In the next few years I think that a lot of the sites I used to frequent, like the escapist, will all start going under. But frankly I think it's a good thing as they were breeding ground for socially inept kids who had moderators just pander to their social inadequacies. If someone is being weird, you should be allowed to say so, because when that kid gets out into the real world, he won't have a moderator protecting him from reality.