An impression is a single instance of an ad, post or search listing being displayed to a person, regardless of whether they click it or interact with it in any way.
Impressions measure exposure, not results. They tell a small business how often it was seen, which is the top of the funnel, but seeing is not the same as acting.
They are the denominator for the metrics that matter. Click-through rate, for instance, is clicks divided by impressions, so impressions give context to whether the response was good or poor.
Rising impressions with flat clicks is a message. It usually means the content is being shown but not compelling, so the issue is the creative or the targeting, not the reach.
A real estate agency's search listings get 10,000 impressions in a month but only 150 clicks. That is a 1.5 percent click-through rate.
The impressions confirm the agency is being shown plenty. The low click rate says the titles and descriptions are not earning the click.
If the agency only watched impressions, it would think things were going well. Reading impressions alongside clicks reveals the real problem: visibility without appeal.
In-House treats impressions as context, not a goal: the agents watch how exposure converts into clicks and actions, and fix the creative when the gap is wide.