Cost-Per-Thousand (CPM) Also known as price-per-impression or CPM for expense-per-mille (mille is the Latin word for thousand), order-per-thousand is an advertising revenue demeanor used by search engines and ad networks in which advertising companies pay an agreed amount for all 1,000 users who behold their ads, regardless of whether a click-through or conversion is achieved. CPM is typically used for Banner Ad sales, while Cost-Per-Click is typically used for text unite advertising.