The basis of an article in yesterday's Sunday Times suggests people are increasingly — and obliviously — being judged by what internet search engines throw up about them, i.e. have you Googled yourself recently?!
The article goes onto suggest that people who socialise on the net cannot erase the consequences of a moment’s stupidity - "Their colourful private lives will sit forever on silently spinning hard drives."
There are lots of examples to make the point - most of which come from the blogosphere or a politician appearing in his underwear on Gaydar. However, their extreme nature arguably glosses over the potential dangers of creating an on-line image of yourself that may not fit with your future self.
Having said all of the above, later on in the article it argued that the absence of a cyber-profile could be damaging too - i.e. you could be viewed as weird for not being mentioned somewhere in cyberspace.
Some remedies are suggested later on in the article, i.e. contacting a "search engine optimisation firm", which can clean up your on-line self. A less expensive or extreme strategy would be to kindly ask the owner of a site you've left a message on to remove it.
My suggestion would be to avoid using your real name except where it is absolutely necessary and Google yourself every now and then to see what, if anything, people have been saying about you. See Focus: Have you been Googled? by John Elliot for more details about digging for digital dirt.