With a pseudonymous identity model, you could simply maintain separate identities for separate areas if you wanted. You wouldn't even be able to manipulate the system that way (say some activity = "being evil"), because as long as you confined behavior that generated reputation for being evil to one pseudonym, the positive reputations for your other pseudonyms that don't mention being evil would actually be entirely correct.
wouldn't this be susceptible to leak if someone finds out your pseudonym, how about system that keep your current reputation rankings (encrypted). and only you know it. system gives your current rep (of some activity) only to people of similair reputation. and that you are making deals with.
