Just because there isn't a paper contract doesn't mean it isn't binding. Make sure a lawyer looks at your terms page in addition to writing the draft. I know that I am indemnified completely with my TOS.
Also, IMO just the presence of a clear TOS is a deterrent for all but the dedicated abusers who don't care about prosecution.
Are you sure you are completely indemnified? There are several jurisdictions where liability from negligence cannot be contracted away. The same is true for breach of warranty and strict liability claims.
Another example is if you are a web service that doesn't comply with DMCA provisions, you may be liable for your users actions.
What I am trying to say is that a TOS does not indemnify as a matter of law. The question of fact for each specific issue will be sent to the jury who will decide your fate.
Whether a TOS creates a contract could also be decided by the jury. They aren't contracts 100% of the time.
I disagree. Some people may be considered judgment-proof, meaning they have no assets to be sued for (O.J. Simpson, for example). However if you win a judgment against someone who has assets but refuses to pay, a court could order wage garnishments and even asset seizure. Basically the courts can make you pay by taking from you. (At least, this is how it works in the USA.)
Of course cases with citizens of different nationality are different and much more difficult to work with, even with a paper contract. Both governments must be willing to hold their citizen up to the agreement in the contract. If I have a contract (printed, signed, and notarized) between myself and the deposed king of Nigeria, it would be hard for me to take the ex-king to court.
Also, IMO just the presence of a clear TOS is a deterrent for all but the dedicated abusers who don't care about prosecution.