71% of blog readers are over 30.
79% of blog readers are men.
21% of blog readers are bloggers themselves.
82% of blog readers say TV is worthless or only somewhat useful as a source of news and opinion (55% say the same about newspapers, 54% about magazines).
50% of blog readers have spent more than $50 on books online in the past six months.

All of this comes from a Blog Ads survey of questionable scientific merit (an online survey advertised through select blogs; even the numbers seem questionable: their site said 61% of blog readers were over the age of 30, but when I added the numbers up they totaled 71%.)