Advertising capping refers to the practice of limiting the number of times a particular advertisement is shown to a single user within a specific time frame. This is done to prevent overexposure and fatigue, ensuring that the ad remains effective and does not become annoying or intrusive to the viewer. Capping can be set by advertisers or ad networks and is often used to optimize ad delivery and budget allocation. It also helps to create a more positive user experience by reducing the likelihood of ad saturation.