Cost-per-Click
From What's new, new media?
Cost-per-Click is an online-specific ad revenue system that pays website owners that host ads based on the number of clicks each ad link receives from site visitors. Although the dominant form of online advertising (as of 2006), it is highly susceptible to click fraud, the act of clicking on an ad multiple times to generate revenue.
As an alternative to Cost-per-Click, Google is experimenting with a Cost-per-Action system, which pays only as a result of some form of tangible consumer action.
