About
An impression is when a ad shows on a web site (property).
It doesn’t take into consideration whether or not the user viewed the ad.
In CPM, the total recorded count of each viewable ad's impressions is what pays publishers.
Articles Related
Viewable
It’s important to understand that:
- an impression measures the delivery of an ad,
- whereas viewable impressions measure whether a user has seen an ad.
See Viewable
Process
To known how an ad is selected and server in order to create an impression. See Serving