If there were enough flyers to match the number of bloggers, buildings would resemble birds instead of buildings. Because the flyers would look like feathers... Yeah, you get it. The point is, the internet is a public domain, so is the public library, the streets, parks etc. It is as dangerous posting private information on the internet as it is on a street corner. Also, if a blogger isn't solely after attention what is the point of a blog? To share opinions and information that may or may not interest other people?... Assuming that people will be interested at all is a gamble, so the real reason must be solely personal. A way to publish and examine day to day life and compare alongside other human beings. We're not interested in the interests of others, we're interested in the lives of others, which is a pretty scary thought. Facebook and Twitter take this to the extreme, providing real time updates and a hub for varying personalities.
To wrap up I'd like to point out that Blogs aren't as harmless as they seem. Compared to Facebook, yeah, they're alright, but to reiterate: The internet is a public domain. I'm not a paranoid freak, just a techno-realist.