Last night at Search Engine Land I reported that Google Penalizes Google Japan For Buying Links. In short, the Google Japan team took on a marketing initiative to of paying bloggers for reviews, that turned out to be paid links, which they did not know was against Google's guidelines. In turn, Google's search quality team slapped Google Japan with a PageRank penalty, from a PR9 to a PR5.
Danny came back into my post and added some history to the discussion, which is valuable if this is new to you.
Many don't understand why Google would penalize themselves. But some suspect it is a PR stunt (public relations). Others think it is just Google manning up to their own policies and doing what is right.
It will be interesting to see how long the penalty lasts. If it was an ordinary site, they could submit a reconsideration request and Google can restore the PR fairly quickly. Would Google make their own sister site wait even longer to appease the public? Or will Google treat this like any other site?
There are many implications to this and this is not the first time Google penalized themselves. They did so with when they found themselves cloaking content.