An ad impression is counted every time your ad is displayed on a user’s screen. This could be on a website, within an app, or across a social feed. Impressions measure visibility at a foundational level, representing how often an ad is served. However, they do not indicate whether a user has seen or engaged with the ad. Impressions are useful for understanding reach, but they are only one piece of the puzzle. To evaluate real effectiveness, impressions should be analyzed alongside viewability, engagement, and conversion metrics.