for goodness sake... if you don't like what you find and you have chosen anything that people may relate to you then change your username. Admin charge a fee of approx (well that is what it I think it cost me to change mine)
It is really only an issue if you want it to be.
eg. My ex knows that the word 'splendid' makes me laugh. If she pieced together that and the fact that I swing.. and then also managed to find my advert she would recognise the picture on the advert that I have and may also recognise my nether regions off my avatar. Then, for it to be any real issue, she would have to prove it were me. From there, what could she do................mmmmm I have no idea. She could 'tell on me' but as no-one in my life would really care less it wouldn't be an issue.
I presume that those who have an issue with security and jobs etc.... would be even more discreet and would use words and pictures that are untraceable.