Definition & Meaning of "viewability"

What is "viewability"?

Viewability is a metric used to measure whether an online advertisement was actually seen by a user. It focuses on whether the ad was displayed on the screen long enough for the user to notice it. Typically, an ad is considered viewable if at least 50% of its pixels are visible on the screen for a minimum of one second for display ads, or two seconds for video ads. Viewability helps advertisers determine the effectiveness of their ads in terms of visibility and engagement, ensuring that their advertising dollars are spent on ads that are seen by real people.