The approval process is hurting more than its helping. I too have had a couple friends give up on the site. I don't see how it really helps. If a troller wants to troll then they just have to make 20 clean posts then they are in the clear to go berserk.
I just about gave up too. Signing up is an impulse decision for most people I think. I lurked forever with no intention of ever posting, but one day, something is said that makes you want really comment on it. But you post and it doesn't even show up. By the time it does, then no one even sees it anyways. Thats a huge turn off. Its an instant gratification thing. I think you have to hook the poster right then and not give them a chance to lose interest. Which can happen easy if they aren't part of the conversation that drove them to sign up in the first place. Its already feels like a pain in the butt to sign up to websites just to comment anyways.