Saw this ad recently somewhere (it's not a Google AdSense ad):

http://blogoscoped.com/files/buy-checkout.gif

I was wondering why what seems to be an ad from Buy.com would want to promote Google Checkout too. Asking Google if the two companies have any business relationship, Google says: "Buy.com works closely with Google and uses a wide range of Google services to support their business, including search, our ads programs, Google Checkout, and others."

I guess it's because their customers can only save $10 if they use Google Checkout.

(There was a Google Checkout promotion launched a while ago which meant Google would reimburse the business $10 when someone placed an order using Google Checkout.)