CPC

Cost-per-click pricing charges advertisers a fee every time a person (well, ideally a real human being) clicks on an ad.

Google perfected this model, and the auction-based pricing associated with it, to amass its fortune. Any publisher can charge per click, and many give advertisers a choice as to whether they want to pay based on clicks, impressions, or other criteria.

While advertisers pay for the click, clicks themselves have little value beyond signaling the clicker’s curiosity or interest. What is most important for the advertiser is to determine the value of what the clicker does post-click.