My favorite magazine is Real Simple. In their September 2008 issue they recently decided to deal with blogging etiquette.
#13 A friend has a blog, and you feel that she is embarrassing herself by giving away too much personal information. How can you tell her?
SMITH: Say that you love her blog but since some readers don't know her as well as you do, they may misinterpret what she's saying. If she gets defensive, back off. But if the information on her blog is creating a safety issue--like she could be attracting a stalker--you're morally obligated to tell her.
SCHWALBE: I'd pose it as a question, such as "How do you decide what's too personal for your blog?" That gives her the opportunity to proclaim a philosophy (in which case, it's her business) or to admit that she doesn't have one. In that instance, your input might be welcomed.
FOX: Unsolicited advice is hard to give, but it is necessary to speak up in a situation like this. Before giving specific examples of content you find troublesome for her professional or personal life, make it clear that you are saying something only out of concern and not judging her.
Whew! Glad to get that information out there. Now, I can morally give you unsolicited advice that you just might just welcome. Be prepared!