The Inside AdSense Blog announced that Google has launched referrals 2.0, or Pay Per Action, to all AdSense publishers who have the referrals option.
Many people only had referral products for Google products, such as AdSense, AdWords, Google Toolbar, Firefox, Google Pack and so on. Now, you have access to thousands of referral products from any AdWords advertiser who set a campaign up.
This should help improve the lack of impressions with Google PPA that we have noticed since they launched the beta.
I have tons of coverage of how it all works in my past articles. I have been beta testing both ends of the product since they launched, so you can probably learn a lot about it by reviewing the Google Pay Per Action archive (tag).
Remember, referral products, including pay per action, can be advertised and promoted more heavily than standard AdSense ads. So you can ask people to click on your ads. And they also include Google's text link ads, such as this one .
Forum discussion at WebmasterWorld and DigitalPoint Forums.