Keltie's blog (I don't think she gets as many comments now as she used to since she's not with Ryan anymore, but she still has a decent following. although she doesn't reply to them.)

I think twitter has greatly changed the way we interact with some famous people -- look at the MCR boys and Tom Felton, who respond to their tweets, compared to other how mostly tweet just to entertain us or something.

If you're looking for people who are famous within fandom-type circles, there's always copperbadge.