Time Capping
This is a special case of
Frequency Capping when you don't want a visitor to see the same
ad again for a period of time.

Example - Limited Exposure
A premium ad does not show to the same visitor within 24 hours. This means if the visitor already see this ad once, he/she won't see it again for at least 24 hours. This can also increase available ad inventory for other ads.
Example - Sequential Ad Display
If you have multiple ads in a zone and want them to rotate from one to the next, you can apply a time-capping setting on each of the member ads. For example: if you have 10 ads in a zone and the serving code is set to auto-refresh every 1 minute. You can set a 10-minute time-cap for each of the ad. This will make sure a full round is displayed and an ad will not display again until all other ads have done so.