Google is experimenting something very different with Referral Ads [also known as CPA Ads].
Google Referral Ads for text links are now contextual like the regular AdSense ads meaning that Google is displaying referral products that relate to content of the web page where that unit is placed. Here are two real examples to illustrate this:
1. The article on recording Skype calls shows a Google referral ad for "Free International Calls" though it’s meant to show only ads for Google Pack.
2. The web page about downloading vista wallpapers shows Google referral ads about "wallpapers and related software" though the unit is again meant to display text link ads for Google Pack only.
Google is clearly overriding the settings specified by the AdSense Publisher.
I have also noticed that Google Text Link Ads may or may not display on a web page even if the product is available for the region where the web page is being viewed from.
If Google ultimately decides to make these Referrals Links as contextual, it could have a major impact on the affiliate industry. You are free to promote referrals any way you like and if the referral product is related to the content, the conversion rates could be much higher.