Throughout the digital marketing world, marketers define impressions as “the number of times an ad is seen.” Google defines impressions as “the number of times your ad is shown on a search result page or other site on the Google Network.” At a quick glance, the two definitions may appear similar. However, there are two words that separate the two definitions, seen and shown.
Facebook has been working hard to give marketers more accurate data by only counting an impression if the ad appears on a user’s desktop screen or on their mobile screen via an app–striving for the seen definition. They are calling these impressions “viewed impressions.” Lets say for example an ad appears on a user’s desktop screen towards the bottom of a page but the user does not scroll down far enough for the ad to appear in view, Facebook would not charge the advertiser for an impression because the ad was not viewed by the user.
In comparison, as they state in their definition of an impression, Google charges an advertiser with an impression each time an ad is shown, regardless if it appeared in the view of the user or not.
It is still important for advertisers to know how often their ads are appearing, regardless of whether or not they’re being viewed, so the total impressions number still has some value. But the viewed impressions technique that Facebook has been using allows advertisers to have better insight into their campaigns while only be charged for ads that people presumably have the opportunity to lay their eyes on.
In a recent blog post, Facebook had the following to say about their viewed impressions:
“Not all ad impressions are created equal. Viewed impressions add an extra layer of analytical rigor, as well as common sense. They more accurately define delivery and help ensure that people have seen the ads they’re supposed to see.”