Facebook’s CPA campaign is the first highly targeted real and potentially effective solution to the app marketing and discovery problem. Hard to believe it took nearly 5 years to see solves for such a fundamental problem. Let’s hope the numbers add up for reasonable ROI.

Marketers opting for CPA bidding are only charged when someone downloads and installs their app. Based on internal Facebook tests, the company said buying on a CPA basis, on average, results in a 20% lower cost per install than through CPC. The new video creative and CPA-buying options will roll out over the next several days to all developers and advertisers.