What is CPM (Cost per Thousand)?

With the CPM bidding strategy, advertisers pay based on the number of impressions their ad receives. For example, if a website publisher charges $2 CPM, that means an advertiser must pay $2 for every 1,000 impressions of its ad. The “M” in CPM represents the roman numeral for 1,000. CPM is the most common method for pricing web ads.