Not surprisingly, the most active bloggers are younger people who have grown up during the blogging "revolution", which started about seven years ago. Bloggers in the 21-to-35 year-old demographic group account for 53.3% of the total blogging population.
Marketers are still coming to terms with the fact that the customer potentially has as much voice as the brand.
Basic analysis from Sysomos but still worth a look. I'd love to see an analysis of the differences by country of Facebook, Twitter and Blogging.