I would suggest you review your understanding of Trademark law before offering similar advice.
Ianol, but just because its on the web, trademark law doesn't simply go away. if you use someone elses trademark without permission you can face legal trouble.
Your name, my name, and Obama is not a trademark ... "trading under the name".
I wasn't referring to trading names, however it is possible to use a spoof of a traded name if it is clear that it is spoof ... those that own the traded name may well try to contend that it is clearly indicated enough that it is spoof, especially if the spoof is denegrating those that own the genuine trade name. The same way that TV spoof programs are made, in particular of the royal family, and of the government ... and who deserves spoofing more than the government ... it seems that they themselves are spoofing government. I don't think we need to get our knickers in a twist too much about it ... no company is going to take a teenage game-player to court over using "some rank names for my own personal use".
A person on another forum could use the name agent_c for example. You do not have copyright.