Google is inviting their network publishers to participate in pay-per-action advertising. The new ‘content referral network’ will pay publishers each time a click on a Google ad on their site generates a sale, a lead, or some other action defined as desirable by the advertiser.

The implications are huge: If the largest online pay-per-click network starts to offer CPA (cost per action) advertising, too, what will advertisers choose? CPA, of course…