| 摘要 |
Impression frequency of displayed content may be regulated by data processing apparatus by receiving from a content sponsor content items and information relating to an impression frequency with which one or more of the content items is to be displayed a viewer, maintaining a history of content items displayed to the viewer, receiving a request for content to be displayed to the viewer, selecting a content item from among the received content items based at least in part on the received impression frequency information and the viewer's maintained history, and providing the selected content item for presentation. |
