The latest issue of the Journal of Computer-Mediated Communication has an article by Mark Tremayne et al., "Issue Publics on the Web: Applying Network Theory to the War Blogosphere."
The authors offer rich descriptive statistics of both conservative and liberal blogs, and correlate blog popularity with a number of likely explanatory variables. Because blogs often provide external links as well as commentary, the authors also apply basic network centrality metrics (degree, betweenness, closeness) to those networks. The result is a clear (if not exactly unexpected) picture of the blogosphere on a critical political issue.
Thanks to Alexander Schellong at Harvard's Complexity and Social Networks Blog for the tip.