One of the most censored places I've ever run into. If you have an idea that's against the hive-mind, you will get voted down the more you talk about it. That I can live with, but many forums on there will outright ban dissenters. It gives the impression that the whole world only thinks a certain way.
Then you go to an unrelated forum to discuss an unrelated topic and your "karma" is too low to participate. Rules are very selectively enforced.
A place that's supposed to stimulate discussion and sharing of ideas? Not what is happening at all. Really, the only mainstream place where there is actual free flowing conversation now is Twitter.