Original paper here. One observation: neither San Francisco or San Diego come out particularly high - although look at that, in indie music San Francisco is less influential than San Diego. Oooh! That has to hurt!
What's really interesting is Los Angeles, the center of the music industry, is only third in indie music, and the first two nodes are both Canadian. Now before you indie fans get too proud ("of course L.A. is only third, it's indie music!") notice that L.A. doesn't even appear on the hip-hop network. You corporate shills.
(H/T Marginal Revolution)