CPM or Cost Per Thousand is a recognized industry standard measure in advertising representing ad impressions. CPM equals how much an advertiser pays for 1,000 impressions of its banner.
Cost per impression, often abbreviated to CPI or CPM for Cost per thousand impressions, is a phrase often used in online advertising and marketing related to web traffic. It is used for measuring the worth and cost of a specific e-marketing campaign. This technique is applied with web banners, text links, e-mail spam, and opt-in e-mail advertising, although opt-in e-mail advertising is more commonly charged on a cost per action (CPA) basis although sometimes CPM is used.
An online advertisement impression is a single appearance of an advertisement on a web page. Each time an advertisement loads onto a user's screen, the ad server may count that loading as one impression. However, the ad server may be programmed to exclude from the count certain nonqualifying activity such as a reload, internal user actions, and other events that the advertiser and ad serving company agreed to not count. For online advertising, the numbers of views can be a lot more precise. When a user requests a web page, the originating server creates a log entry. Also, a third party tracker can be placed in the web page to verify how many accesses that page had.