Go here for an introduction to the product criteria list.
The idea behind this point is very simple: If your customer earns money through your service (or saves money) he is more likely to pay for it. Ideally you get a percentage of the earned money. So your win scales with the success of your customer. eBay is a perfect example of this. Each time something is sold on eBay they get their share. Try to place yourself directly in the middle of a transaction (although this is not always possible of course, but you should make sure that you get as close as possible).
It is also important to remember what you are selling. Its not the technology, its not the fancy new programming language, nor is it the framework your product is built on (most customers haven’t even have heard of them). Its the service you give them. Its the time they save through your product. Its the thing that makes their lives easier. Thats what they are willing to pay for.