Watch this space, because it is almost certain to be the next big thing, after Adsense.
CPA networks are not new, but they’re a natural fit with search. It’s only a matter of time before the search engines come out with similar products. Google is currently testing such a model.
CPA solves a lot of problems of CPC, on both the advertiser and publisher side. The publisher, if they are astute, should be able to achieve higher prices per click than with distributed CPC networks. The advertiser should be able to avoid click-fraud.