Alexa vs. Technorati: charting the top liberal political blogs

Compared to the conservative blogs in the Technorati 100, the liberal political blogs show slightly more agreement in their chart.

Talking Points Memo and Think Progress both show less traffic than links. Maybe they have a solid core of regulars that link, but don't draw a large number of unique visitors?

Crooks and Liars gets comparatively more traffic. Why might this be?