Google Whispers More Details About PPA -- David A. Utter | Staff Writer

The pay per action beta test for Google AdWords recently debuted, and spurred plenty of advertiser interest.
Since last week's announcement that Google would start offering AdWords PPA ads, where the advertiser pays only when a predetermined conversion has taken place, plenty of buzz has swirled around the plan.
A lot of that buzz has focused on a few distinct questions about PPA on AdWords. The Inside AdWords team at Google posted answers to some of the more frequently asked questions they have received about the plan.
International advertisers will have to wait to participate, as Google has opened this limited test only to US-based clients. Advertisers must have a billing address in the United States, so even if an international business focuses on US customers, that isn't enough to be eligible yet.
PPA ads only show up through being displayed on sites that participate in Google's content network. They won't appear on Google or in its search network.
An advertiser concern of content networks has been the prospect of being displayed on less than desirable partner sites. Since the condition of PPA requires some kind of conversion to take place, typical worries about click fraud with pay per click ads should not be a problem.
On the content network side, AdSense members can sign up for a referrals program. Search marketers managing clients through the AdWords 'My Client Center' product can select individual accounts to participate in the PPA beta.
The fixed rate provision of PPA through the new program probably won't change in the near term. Some advertisers had asked about paying the PPA as a percentage of a sale, but Google is only doing the beta with a fixed price as the cost of conversion