At my next job, I'm not going to let people know I have any internet presence. I have a very distinctive name, and when I'm googled, all that shows up is my name from when it was printed in a local newspaper when I graduated high school.
No one needs to know about my site. my livejournal, myspace, and facebook are all friends-only, and I don't need to add anyone I work with... even if they search for me by name, all they'll find is a picture, a tagline, my location, and a message saying they need to be my friend to see more.
Why does a coworker need to be that kind of friend? You see them every day; I saw my coworkers more than I saw my real friends. They don't need to be my online chums.