> Did you agree to the rules of the party before joining? Yup. One of which is: "Use your real name".

I signed up for Facebook in September 2004. I most certainly did not agree to that rule, because as far as I can recall, no such rule existed at the time. You may make the argument that my continued use of their service implies assent to any subsequent modifications to their terms of service, but that's an issue that would need to be litigated.