Problem: The PF forums seem deader than they really are because all new posts aren't immediately visible when entering the forums front page. For example if any subforum e.g. "Newbie Topics", has received more than one new post, the only way to view the new post topics, or even know if more than one post is available, is to click into that subforum. With the large amount of subforums this takes a lot of time and leads to a large portion of new posts being ignored.
Solution: Adopt a format similar to the one in the attached photo. The new format displays all posts on the entire forum by default, BUT if a user wants to filter and only view topics from specific subforums he can simply click the appropriate box and viola: instant filtering. Users who are mainly interested in certain topics can save their user settings to show these topics by default when they login.
Don't get me wrong, the forum indexing is extremely helpful, but the implementation is not. IMHO, without question my suggestion will lead to more forum views, more forum participation, and cause more users to log-in instead of view the forum as guests.