Interesting ads in google ads

what can you see in this google ad.. do not worry.. it's just a image..


<< facebook ads marketing










<< yahoo ads marketing



So facebook and yahoo have both taken a step forward to advertise their advertising ad in google adwords. So what if google was to advertise in facebook and yahoo ads?
so basically they are all just doing free marketing? since the money they earn from one will just be used to advertise back. Circular advertising.. sounds rather cool

source : http://www.techcrunch.com/2007/11/28/straight-out-of-left-field-google-experimenting-with-digg-style-voting-on-search-results/