TL;DR
Also called cost per thousand (CPT), the Cost Per Mille pricing model charges advertisers a fixed price for every 1000 views/impressions, regardless of the fact that the ad was clicked on or not. It is a very commonly used advertising method especially when the goal of the campaign is to generate awareness and when the click through rate (CTR) is not relevant.
About CPM
The Cost Per Mille or cost per thousand advertising impressions is one of the main ad pricing models. Although it is very frequently used, CPM does not necessarily indicate the effectiveness of an advertisement/campaign. So when advertisers aim to increase conversions such as sales or registrations, they often prefer to choose other pricing models, such as cost per click (CPC) or cost per action (CPA) for planning their budgets.
When is the Cost per Mille used?
CPM is recommended to be used when the purpose of the ad is to generate brand awareness and for the ads in which impressions are more valuable rather than clicks in general (e.g.political campaigns).
