Anonymity and Code Project

For those on here with pseudonyms, why do you do it? Is it out of fear, just for fun, your real name was already taken by somebody? Do you do it so that you can bad mouth people without them knowing? Are you a celebrity and you just want to be a normal 'Joe'? Are you evading the law? Is it just a reflex and you don't care if somebody finds out who you are? Are you Batman?