Frequency capping is a technique used in the online advertising industry to limit the number of times that an ad is shown to a particular user or audience. Frequency capping is typically used to prevent ad fatigue or over-exposure, which can reduce the effectiveness of an ad over time. Frequency capping is often implemented through the use of cookies or other tracking technologies, and can be customized by advertisers to meet their specific needs and objectives. For example, an advertiser may choose to cap the frequency of their ads at two impressions per day, in order to ensure that their ads are shown to a user at a reasonable and appropriate rate. Frequency capping is an important tool for advertisers, as it can help to maximize the effectiveness and value of their ad spend.