What software do sites like www.shopzilla.com, www.become.com, www.kelkoo.com etc.. use for the Pay-Per-Click product listing campaigns they offer for their retailers. I am asking what kind of software do they use to know that a certain retailer's products has been clicked 50 times or 100 times(and then the cost of the click is deducted from his money-account) etc...

Can someone point me to those kind of softwares?

EDIT

*Some Explanation :: *

In a site like www.shopzilla.com, retailers will upload thier products(list their products on the site). Anytime a buyer clicks on a product to go the retailer's website, an amount of money(say $0.20) is deducted from his account(the money he has deposited in his account with shopzilla). A retailer can see how many times buyers have clicked on his products and how much money remains in his shopzilla accounts.

Am looking for such softwares that comparison sites like shopzilla uses to run this type of campaigns.

I hope it is clear now.