oddity: google ads… on a yahoo site?!

Am I the only one who has noticedthat Flickr is showing ads from Yahoo, it’s parent company, and Google?

GoogleYahoo

It would seem that Flickr is making money off Google’s AdSense programme and Google is making money off of Flickr showing it’s ads – a mutually beneficial relationship, sure, but somewhat surprising considering the rivalry between flickr’s owner Yahoo and Google.