A national phone survey found more than 44% of adult Internet users used the Internet to publish their thoughts, respond to others, post pictures and or share files.  Yet only 2% of Adult Internet users have blogs while in 2004, between 2% and 7% of adult Internet users have created diaries or blogs.  This survey showed 11% of Internet users have read the blogs or diaries of other Internet users and a third posted material to blogs.

You can read the survey here.