Via the Guardian, The Hockey Stick Illusion was number 2 on the green bestsellers list for 2010. There are also several other well known names on the list, but these have release dates in earlier years, so it's perhaps not quite as amazing as it looks. Nevertheless, in view of the failure of most MSM outlets to review the book at all, HSI's performance says something about the power of the blogosphere and the failure of the MSM.
Guardian coverage here.