They have already, click the link in post #8. Here it is -
http://www.benedelman.org/news/111111-1.html
Stuff like -
http://online.wsj.com/article/SB10001424052748704058704576015630188568972.html
How about PPC?
You hear Google talking about thin affiliate sites, have Google Slapped some affliates using PPC because of that but......
http://adwords.blogspot.com/2009/11/announcing-product-listing-ads.html
Slap an affiliate put their own ads in place.
"Pay only for results: Product Listing Ads are charged on a cost-per-action (CPA) basis, which means that you only pay when a user clicks on your ad and completes a purchase on your site."
Google is basically an affiliate themselves.
They own an affiliate network and guess which merchants are in those ads? The ones in their network.