Ha what they did is a 302 redirect on themselves. Mod rewrite domain.com $www.domain.com as a 302 type redirect and the google duplicate content filter banned them. Better go check your htaccess files guys this MUST be a 301 or you will get booted out of the SERP's.
I also found googleguys post in another forum that the article refers to.
(i.e. "site A appears to have duplicate pages from, or is doing a 301/302/whatever to site B, and Google is wrongly picking site A as canonical", with actual values for A and B), I'd be happy to hear them. Drop an email to webmaster [at] google.com with the keyword "canonicalpage" (all as one word) and I'll ask someone to collect the feedback and pass it on to an engineer.
anyone who has been hijacked start sending then e-mails of known examples.