Sixty of the top 100 Twitter users are bloggers. The analysis takes the top 100 Twitter users as measured by the number of followers. In April 2008, a list was created from the website Twitterholic, which ranks Twitter users by the number of followers.
According to my categorization, the breakdown for the number of users in the top 100 is as follows:
Of course, the number of followers is only one measure. It does not necessarily indicate the usefulness of the Twitterer. I am working on a different measure that will provide another metric to evaluate usefulness.
One caveat, the list is in flux. Barack Obama was recently toppled from the top ranked position by Leo Laporte. (As of today, Twitterholic appears to be malfunctioning—the usually high ranked users are missing from the Top 100 list.)