A search for the term "google adsense" on Google shows the following results. Note the top one...it evidently isn't from Googles website (Look at the website address).

This is the most profound demonstration of a technique named PageJacking, where one website can manipulate a search engine to steal another websites search engine rankings. The fact that this can happen at all is due to a major flaw in most search engines - not just Googles.

A more detailed analysis will demonstrate what is going on. By getting Google to load its results for the website in question you can see, that Google thinks the website is actually theirs, and that is the crux of the issue.  Because of a flaw in the handling of redirect commands both 302 and HTTP-EQUIV="Refresh" this website has been able to hijack the valuable assets of Google in order to achieve a high positioning.

To demonstrate, you can see that the website has picked up both the backlinks and the PR9 status of the target Google Adsense page, and notably even Netcraft are confused by the redirect and think it is actually coming from Google.

I have seen cases of this before, and its been a hotly debated topic for a number of years. However I have never seen it perpetrated directly against a major search engine.

Hopefully this will be the straw that breaks the camels back, and gets the them to do a stock overhaul of the way they process redirect commands so that this cannot happen again.