I never use my real name when posting on the Internet. You'd be surprised what kind of profile can be created of someone when searching through their past posts, especially when compiling several years worth of information. I learned my lesson a few years ago when I used my real name when posting to Usenet. Now, all those controversial and even embarrassing posts are still there for everyone to see simply by doing a bit of searching.
Think about all the personal information people post about themselves here on Flyertalk. Not a whole lot in each individual post, but when taken together one could put together a very good dossier of an individual's jobs, place of residence, hobbies, interests etc. at a given point in time. And now realize that all this information is available to anyone willing to do a search, even several years from now.
Call me paranoid, but I value my privacy!
Still remaining,
freeflyer