To my mind the rules forum has been dead for a long time now. Except for the occasional new question from a brand new supplement, the rules have been argued to death by now. Newbies come in and ask the same old questions, people continue to argue the same debates convincing no one of their side.
Whenever a new book comes out, you get a brief resurgence where new questions are asked, but other than that there isn't a lot of new info going on anymore. Once 4e comes about that will change drastically. This forum will likely be the most popular, as we start going through the system and hammering out the details.