Earlier today I noticed a link from Mike Torres to a press release from ComScore Media Metrix entitled The Score: Blogs Gain Favor Worldwide which states

In recent years blogs have garnered significant media coverage in the United States for their ability to reach a wide audience. With more than one-third of the online population in the United States visiting blogs within a given month, it is clear that the category has become mainstream. An analysis of blog penetration by country in North America and Western Europe shows that the popularity of blogs is a worldwide phenomenon.
...

• Windows Live Spaces is the favorite blog site among the majority of countries studied, with 37 percent of all Canadians visiting the site in October 2006. Blogger.com had the highest penetration in the United States (12.4 percent) and Germany (9.7 percent), while the same was true for Skyblog in France (27.4 percent).

Interesting statistics although I wonder whether ComScore is including social networking sites like Bebo and MySpace in its reckoning. Based on how ComScore usually scores things my assumption is that they are going by number of unique users instead of page views which is where heavily trafficked social networking sites like Bebo and MySpace reign supreme.