I can;t find the source now but somewhere I read today that KOS is 2 for 20 in winning candidates.
He sounds more like the Kingmaker for Loserville.
According to a Weekly Standard article Kos raised money for more than a dozen candidates in the last cycle and... All of them lost.
Depending on how you count it (what's success in lefty blogland?), the liberal blogosphere as a whole hovers around 0 for 20 (source: Weekly Standard again).