Blogging rules of engagement?

I was chatting with a coworker as we were both here late last night about personal blogs. He said a friend who never even mentions he has a daughter on his blog, because he's afraid someone will put two and two together and go to her school to kidnap her.

I think that's a little extreme. I know I've toned down the personal references on this here blog with the realization of how simple it is to, as he said, put two and two together. But how far should you take it?

What precautions, if any, do you take on your blog? Do you tell people about it? Mention your personal life? Where you live? Your name? Friends and family? I do all of the above -- in moderation. Just curious what the blogosphere thinks.