Paydotcom is an affiliate promotion center, much like Clickbank, which allows you to sell digital products too.

It's free to join and ANYONE can create a product and promote it there.

One of the things to look into when promoting a product is the Paydotcom APS score, or what is known as "The Affiliate Power Score."

Here is how Paydotcom explains how it is calculated:

This score is calculated on a daily basis and it depends on a number of factors such as the number of sales, total refunds, and affiliate earnings with special emphasis put on the number of unique affiliates making sales over the last 150 days with recent transactions having more relevance. There are other factors including the amount the affiliate earns and others but we do not publish this algorithm to protect the integrity of the score so that it is not manipulated in any way and it will always represent the most accurate representation of top products to promote for affiliates.

Right now you can become a Paydotcom member for free as an affiliate to promote somebody else's products OR as a product vendor to sell your own products. If you want to sell multiple products, the cost is only $29.

It's the quickest and easiest way to generate your own affiliate army. (And to build up your own Paydotcom APS score.)

Clickbank has a similar secretly-calculated formula to help affiliates compare the saleability of their products, which they call the gravity score.