Just received an email from Google on their new pay-per action advertisement.
What this means is you can select products and services from their Adwords advertisers and match them with your site's content. This results in more relevent and best performing ads on your site.
You will have earnings when your visitors click through to an advertiser's site and complete an action defined by the adveristers, hence you have a higher earnings for your site.
They are in a beta test and if you're interested you can sign up as a beta tester.
Inside AdSense: Now accepting applications for new referrals beta
