Wow. I am part of an elite group (aka minority); I’ve published a little before, keep a blog, read blogs, write mostly "business" related stuff and use my real name (read this to figure out what I’m saying!).
The skew is towards young folks, probably influenced heavily by a site like MySpace. They’re the ones that write the not-for-sale personal stuff. But I think bloggers are mostly senior consultants/small-businesses sharing their wisdom (pure anecdotal speculation).
Blogs are notice boards. People put stuff up for others to see. I’d keep a "Dear Diary" offline journal if it was not for public consumption. I’d like to share my experiments with you and not just spend time writing about it for personal reasons (it’s already in my head for me!). And I think that idea powers us. Of course, search engines make it easy to seek out these "homepages" and listen to what others like us are talking about. I believe in collective wisdom. Blogs do just that.