[icedchai]

I think you missed the point. They can't prove it was him actually filling out the registration form, only someone from some IP address at a specific time. They can't prove the person who logs in using that registered username/password is the same one that accepted the TOS.

ToSes are mostly useless. They generally contain a line that indicates the terms can change at any time and you accept them by continuing to use the service.

[aflag]

I guess you'll need to convince the judge that there's reasonable doubt that you did not create the Facebook account that you use and that you were unaware of the ToS and not acting in bad faith. Not saying it's impossible, but it's not as difficult to enforce the ToS as it has been suggested. They are certainly not useless.

[icedchai]

They are useless in that reading them is pointless since they can be modified and/or enforced arbitrarily. If you violate the ToS, the site might kick you off. If you do something the site doesn't like, they can change the ToS and kick you off anyway.