Why impressions matter
Impressions are the denominator. Click-through rate, cost per thousand, and share-of-voice math all start from how many times the thing appeared.
Movement in impressions also signals reach itself: rankings gained or lost, ad delivery throttled or expanded, before clicks change at all.
How impressions are counted
- AdsCounted when the ad renders, with viewability standards for stricter counting
- SearchCounted when the listing appears on a viewed results page
- EmailOpens are the closest equivalent, with known accuracy limits
- SocialCounted per display in a feed, including repeats
Questions
Impressions vs reach: what’s the difference?
Impressions count displays; reach counts unique people. One person seeing an ad five times is five impressions, one reach.
Are impressions worth optimizing for?
As a diagnostic, yes; as a goal, rarely. Impressions without clicks and conversions behind them measure presence, not progress.