In the context of advertising, frequency refers to the number of times that an ad is shown to a particular user or audience over a given period of time. Frequency is often used as a measure of the effectiveness of an advertising campaign, as it can indicate how well an ad is resonating with its audience and how well it is meeting its objectives. High frequency can be a good thing, as it can increase brand awareness and familiarity, and can drive conversions. However, high frequency can also lead to ad fatigue or annoyance, and can reduce the effectiveness of an ad over time. Advertisers often use techniques such as frequency capping in order to ensure even delivery, or creative rotation to manage the frequency of their ads in order to avoid these negative effects.