Meaning you haven't given a donation to Hip Publishing. You get more file room, you can use custom avatars, and you can change your title 'member, senior member, or earth' in my name. Go here: http://hipforums.com/forums/subscriptions.php?
you can also change your custom title when you reach 1,000 posts and you've been here a certain amoint of months...when you sign up you also get your own personal forum.
Oh yeah, I forgot to tell about the personal forums. Heh, I've been waiting for mine for like 2-3 months now though. But yeah...