MyBlogLog is a hosted community service that adds to blogs via widgets in sidebars. Via MyBlogLog, blog owners can have their own little community. However, the actual user names are maintained and owned by MyBlogLog.
From the about page:
Readers can become friends with other people who read your favorite blogs. See what else they’re reading. Check out their MySpace and Friendster profiles and view their Flickr photostreams. Authors can learn more about their readers individually and as a group. What do they like and what are they ignoring? What are they reading elsewhere on the Web?
MyBlogLog was acquired by Yahoo in January 2007.