If you love to write, like I do, it becomes difficult to add new posts to a blog frequently with all the biz and personal stuff going on. I simply don't want to post random nonsense on my blog. I have a friend who posts constantly on his, and some of it is uninteresting (to me) and often very poorly written, which drives me nuts sometimes. Just looks and reads too rushed and haphazard for my tastes.
I don't necessarily care to read about someone's random boring activities. It then becomes a further waste of my time. But if someone is writing about something inspiring, compeling, thought-provoking, etc., then it has purpose and value.
Just my opinion about blogs.