Please go to your preferences page and make sure your "See Mature Topics" setting is set. Setting it to "Yes" means you see the Mature Topics forum (contains political and religious debates). Setting it to "No" means you do not see those threads.
Ever since the bar was lost that told you who was in there, no one has really bothered any more. You're welcome to join the IRC room though, there's always people in there... although the same can't be said for activity! XD