First off, this is a forum. A forum's sole purpose is for you to discuss things. If you're not going to add your thoughts to a thread, simply don't post in it. These one word posts, posts with only a smiley, and posts that just quote another member's thoughts should be against the rules. I know a lot of people in this world that will be instantly turned off if they see this type of behavior being openly allowed. At least type "I agree" into the post when you quote someone.
Second, why all of these subcategories? So much breaking down of subjects defeats the purpose, methinks. If your member count declines, population will fall flat, and I think that because of this, the numerous subcategories should be merged into one, large board parent.
Also, I would like to suggest merging of the forum rules and the forum news section. It looks sloppy to have so many seperate places, IMO.
And finally, I think that the mandatory requirement should be moved into the newly merged "Forum Center" or whatever you wish to call it, and should be renamed to encourage inviting members instead of making it a required duty, as this will scare away a few people as well.
Just my thoughts, discuss please.