Impressions
The total number of times a post was displayed, including repeat views by the same person.
Impressions count how many times a piece of content was rendered on a screen — every time it appears in a feed counts, even if the same person sees it three times. It's a gross exposure number, not a count of people.
That's the key difference from reach, which counts unique people. Impressions divided by reach gives you average frequency — how many times, on average, each person saw the post. A high impressions-to-reach ratio can mean strong repeat exposure or a small audience seeing something repeatedly.
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