What Cost Per Thousand Impressions (CPM) is: A metric that tracks the cost of ad campaigns. It is used in campaigns where advertisers pay every time an ad is displayed—and these impressions are aggregated into groups of a thousand.
What Cost Per Thousand Impressions (CPM) not: Pay-per-click, online advertising wherein the advertiser pays for the ad when it is clicked. Click price can either be a flat rate or determined based on a bidding system. Also, CPM should not be confused as “cost per million.” The acronym actually stands for “cost per mille”—mille meaning “thousand” in Latin.
Why Cost Per Thousand Impressions (CPM) matters: In this advertising model a company has to pay even if an ad or element is not clicked on. However, advertisers can dictate terms to define an impression—excluding refreshes from the count, for example.
Find this post useful? Download our complete guide of key testing concepts with over 120 terms!