I think Doc has a point...
The best bloggers are the ones who actually DO something, then write about it. I know the image in your head is someone talking (whining) about their own problems (that's what Facebook is for right?) but these people will often be ignored apart from their friendship groups. If you actually DO something and then write, it can be interesting.
For example a friend of mine writes a blog about cycling in (and out) of London. He sets himself a task (for example, how far out of London can he get on a train for £30 and what route can he do when he is there) - this is clearly going to be excellent for someone who likes cycling, wants to get out of London for the afternoon, but would like a helping hand. My friend provides maps, reviews (and, of course, pub recommendations). That's a good blog.
If you've ever been on tumblr.com you might find more of what missnemesis is talking abut though...
All the best,
Spare Ed