I know why this blog thing has caught on as it has. It gives some of us "windy" people a chance to just spout about whatever. It doesn't matter if no one reads it or if no one cares. I can write here for as long as I like and if the reader doesn't like it, he or she will just move elsewhere.
And from the reader's point of view, I have always found reading blogs to be a somewhat voyeuristic pursuit. I can read about complete strangers and all their hopes and dreams and opinions. And never have to identify myself or engage in any kind of interaction. It is like peeking into a stranger's life.