I've been thinking about this quite a lot lately, and I have some advice for new bloggers: do it anonymously, at first at least.
There's a distinction between private/public figure which isn't always perfectly clear, but it's something that the internet totally destroys. If you write something on the internet, it's public. A big blog links to it, suddenly you go from 50 hits per day to 5000 in one day. 5 hours later, CNN puts it on their "inside the blogs" segment, and suddenly you've gone national to a non-blog reading audience who are perhaps unaware of conventions of blogging.
I think that until you blog for awhile it's hard to quite get a handle on how much you want to be public versus being private, and how easily blogging and the internet and the media can tear down that wall in a way you never expected.
I'm not saying that everyone should blog anonymously forever, but until you get a better idea of how it fits into your life, I really suggest starting out that way.
