One of the big issues with computer crime is the belief that because the internet is anonymous, the criminals will never be identified. A recent intellectual property case shows that's not always the case. Despite the user creating the site with a pseudonym and PO box, the government was able to track it back to the real person involved.
It's unusual for us to get this clear of a view about how a person can be tracked across the internet. The exact methods used here by the government require the cooperation of the ISPs involved, but it would theoretically be possible to accomplish the same thing by hacking or using social networking connections.
Because internet anonymity is only skin-deep I try to act as if everything I post online is under my real name. I suggest everyone do the same.