CPM (Cost Per Mille) is a common type of online advertising payment model that is used to measure the effectiveness and profitability of an advertisement campaign. CPM means cost per thousand, which means that the advertiser pays a fixed amount for every one thousand impressions of their ad.

The CPM payment model is commonly used in display advertising, where advertisers pay to have their ads displayed on websites and mobile apps. The amount of money paid per impression can vary depending on the location of the website or app, the target audience, and other factors.

One of the key benefits of using the CPM payment model is that it allows advertisers to reach a large number of potential customers without having to spend a lot of money upfront. Advertisers only pay when their ads are shown to users, which can help them control their budget more effectively.

However, the CPM payment model also has some drawbacks. For example, advertisers may not be able to accurately measure the effectiveness of their campaigns, as they are only paying for impressions rather than clicks or conversions. Additionally, the cost of displaying ads on certain websites or apps may be higher than others, which can impact the overall profitability of the campaign.

In summary, CPM is a popular payment model used in online advertising that allows advertisers to reach a large audience without spending a lot of money upfront. While it has some drawbacks, it can be a useful tool for businesses looking to promote their products or services online.