Find out who his ISP is and send them a bunch of letters. In this day & age, they don't want that kind of retarded user. The money lost defending a subscriber is FAR more than dropping them like a bad habbit.
FYI I'd send an email to youtube, more than likely the vids can be restored, easily. Same for picture sites. They're also likely to cut through the proxy BS and IP ban the retard. He more than likely has a static IP too, if his uber l33t hacker ass is scared enough to use proxies. He's definately not smart enough to borrow other people's wireless, that's the best proxy ever invented. :yes: