Clickbank is helping affiliates to earn money. If someone click through ur affiliate link, he will be directed to vendor site (or sales page), if he or she buys something u get affiliate commission upto 75%. For more details visit click bank help page http://www.clickbank.com/help/
Yep. Clickbank is not pay per click. You only earn if you make a sales. If you are looking to earn by the clicks, probably you should look at adsense.