I can least partially answer your question :-)

It's basically the ad-free version of Facebook. However, despite the fact that I poured through the site with a fine-toothed comb, I couldn't find any details, but I imagine you'd need a credit card to get one.

Update: I managed to find a few more details. Among other things, you get the "profile generator" color changer (no clue on that one) and video char, which I believe is still in Beta. Lastly, you can change your "status" like you would in Yahoo Messenger.