Several people around the country have been fired for posting "inappropriate" material on their blog. These include:
I stopped blogging when I started working at my current employer for this very reason. Whether you like it or not, employers can and DO fire people simply for blogging (especially in states governed by at-will employment laws, like California). I will now only be publishing fiction on this site. Anything you read on this site either a) is fiction, or b) was written before I got hired.
If you think it's pathetic that companies can fire people for blogging, join the fight for bloggers' rights at the Electronic Frontier Foundation.