What does viewability measure in the context of online advertising?

Viewability in online advertising specifically measures whether an ad is actually seen by a user. This metric is crucial for advertisers because it helps them understand the effectiveness of their ad placements. For an ad to be considered "viewable," it generally needs to meet certain criteria, such as being displayed on the screen for a minimum duration and being in a visible area of the page.

This measurement is important because it goes beyond simple impressions, which count the number of times an ad was served, regardless of whether it was seen or not. Therefore, focusing on viewability ensures that advertisers invest in placements that genuinely reach their audience, leading to more effective ad campaigns and better return on investment.

In contrast, other options focus on different aspects of user engagement or interaction, such as clicks or shares, which do not directly correlate with whether the ad was viewed in a way that meets established viewability standards.