Traditional direct marketing firms have offered a CPA model for years. It evolved out of a demand for return on investment (ROI). Today, the CPA model is back in style for the same reason in the online world.

Publishers were starting to feel the sting because unscrupulous marketers used the CPA model to spam valuable opt-in lists and other forms of interactive media. What did they have to lose?

The end result was that many companies used the CPA model to analyze their offers risk free. Publishers lost money and were left with fatigued databases.

Off late the ground rules have changed. One difference is that publishers now expect marketers to put a little skin in the game. Publishers are looking for a win-win situation. They've spent a lot of time and money building a precious commodity. They aren't about to squander it by letting a marketer test an offer risk free.

Publishers and CPA brokers expect the marketer to first test the offer in front of a limited audience at their own expense. With test rates as low as $25 per thousand (sometimes lower), a marketer can test an offer to a target audience of 100,000 opt-in recipients for as little as $2,500.