Via Ethan Zuckerman and Henry Farrell, check out this fascinating exercise in mapping the American political blogosphere (and, via Ethan, John Kelly and Bruce Etling's mapping of the Iranian blogosphere; and some discussion here of the methodology's value); also, check out Noor Ali-Hasan's MA thesis using link analysis on the Kuwaiti blogosphere). The methodology and meaning is (sort of) explained here; basically, they chose the "297 most visible and influential websites and blogs", explored the linking patterns, and then produced visualizations like this one (which I, um, completely randomly selected as the experiment):
No real comment, other than that the clustering effects they report do tend to lend weight to the fears of scholars such as Cass Sunstein and Diane Mutz. I'm sure that as people begin poking around there will be all kinds of interesting questions raised about the methodology and how the implications of the findings. Me, I'm content to say that it's awful pretty.