Frequency Capping functionality
Frequency Capping allows publishers to limit the number of impressions served per minute per visitor. Frequency Capping is set at the ad unit level, not the site or account levels. This feature is turned off on all ads by default and must be enabled prior to usage.
Use cases
Some sites choose to use these features to further maximize user experience by minimizing the number of times an ad is shown to a single visitor to help improve engagement with content and ads.
Frequency capping is managed per ad unit and is optional.
How to
You can enable and change Frequency Capping settings under "Inventory -> Settings -> Frequency Capping" for each ad unit.