From Editor & Publisher (covering a Gallup poll on Net usage):

...blogs barely existed until recently and now fully one in five Americans say they consult blogs "frequently" or at least "occasionally." That 20% figure trails instant messaging (28%), auctions (23%), videocasts and downloading music (22%).

E-mailing still heads the list at 87%, followed by checking news and weather (72%) and shopping and travel planning (both at 52%).

In terms of blog activity, there is a slight gender gap (24% of men and 17% of women read them), and of course a generation gap, with 28% of those 18 to 29 using them and only 17% of those over 50.

Nearly 60% still say they "never" look at blogs.