CPC, or Cost per Click, is a metric that is tracked in many branding, direct response and performance campaigns across any vertical. A click often refers to clickthru on an ad that directs them to the advertiser’s website, though many rich media campaigns may count a click on the ad that triggers some engagement (for instance, the user clicks on the ad to start playing a video, or playing a mini-game on the ad unit); in the rich media situation, this can also be referred to as Cost per Engagement (CPE).
A related concept is eCPC, or Effective Cost per Click. This is often calculated by advertisers who pay on another cost basis such as CPM, but wish to convert it to a Cost per Click in order to optimize their media buying to some Cost per Click target.
It is calculated as follows:
( sum of the relevant media costs / total # of clicks )
So, if a display campaign spent $5,000, and garnered 250 clicks, then the the eCPC = $5000 / 250 = $20
