An online ad’s cost per thousand impressions. An impression is a measurement of how many times an ad is shown to a user. Your CPM is $1 if an ad network charges you $1,000 for providing 1 million impressions. If your campaign’s purpose is to create brand awareness, a CPM model can be a viable technique. A cost-per-click (CPC) model may be a better alternative if your campaign goal is to enhance user contact with your brand or push users to do a certain action, such as signing up for a loyalty programme.