This problem may very well grow as IPv6 gains adoption. IP address won't be a viable indicator of identity. What we need is a distributed, pseudonymous reputat

This problem may very well grow as IPv6 gains adoption. IP address won't be a viable indicator of identity. What we need is a distributed, pseudonymous reputation system. In this way, honest users would have no problem signing up for services such as yours, but griefers would have much more trouble, because there would be a very real cost each time they destroyed one of their pseudonymous identities.