You misunderstand.
I blow Krugman's resume off because I think he's full of crap. I don't need bloggers or anyone else to tell me so, although it saves time when someone else does the work of collecting the facts into one place, and there are web pages and columnists (not just bloggers) who have almost made a career out of pointing out his factual mistakes.
This is not just my opinion. Krugman is partially responsible for major changes in the New York Times corrections policy. The history of this particular correction and policy change is worth a thread all by itself.