If it's an IP to say, a library, you're absolutely correct that they have nothing they can use. You seem to be presuming that AOL will be required to give out said information. The fact of the matter at hand is that AOL's AIM is the software in question - so their own people would be enforcing its usage. You're right on not being able to prove who was at the keyboard even on a residential account. AOL solves this by denying its services to the account and not the people at the keyboard. Nobody uses an AOL account once it's 'TOSsed' without contacting AOL directly and addressing the problem.