Jeremy Zawodny lists The 10 Habits of Highly Annoying Bloggers. I'm not so fussy as him: there are only two things that mildy irritate me in blogs.
First, the habit that some bloggers have of linking some words to their dictionary definition at Dictionary.com. This gives the impression that the blogger either thinks he/she is more intelligent than the readers or the readers are stupid. Either way, it is irritatingly patronising.
Second, newly born baby pictures. Although our own babies are the most wonderful things we can imagine, I don't think we feel the same about others. I'd much rather see a picture of someone's pet dog!