Viewability or Ad Viewability is an online advertising metric that aims to track only impressions that can actually be seen by users. For example, if an ad is placed on the bottom of a website, but the user doesn’t scroll down far enough to see it, the impression is served but it is not viewed by the user. So basically, viewability is designed to let advertisers pay only for the ads that users could possibly see.
The industry standard in online and mobile advertising is currently switching from served impressions to viewable impressions. However, the main problem with switching to this new standard is, that there still seems to be a lot of confusion about what a viewable impression actually is. According to the Interactive Advertising Bureau (IAB), a viewable impression is one that is at least 50% visible for at least one second. However, vendors offering viewability solutions might use different methods and technologies to establish whether impressions meet those criteria or not.
Generally viewability is a metric that is related to different criterias such as:
- state of publisher viewability
- page position
- ad format and size
- publisher industry