Contracts are only good if they conform to the applicable laws in the area you want to enforce the contract in. I would enforce it in the US (under Texas state law) so I would file there. It does me no good to file in Texas against a person that lives in the UK. They just don't show up and I win, but, what do I really win when they can't enforce the courts ruling.

I used to run a successful forum. I sold it for low xx.xxx about 4 years ago (when I was 19). However, due to the sales agreement I can't talk specifics