Glossary
Reach
The number of distinct people (or accounts) a post was shown to, counting each person once however many times they saw it.
Also called: members reached, unique viewers, unique impressions
Reach counts people rather than displays. On LinkedIn it appears as “members reached”: the “number of distinct members and Pages that saw your post”, an estimate that “does not include repeat views” (LinkedIn Help). Where an impression is one display, reach is one person.
Reach is the better number for the question most founders actually have, which is how many people saw this at all. It is still silent on who they were. A post that reaches a few hundred people in the industry you sell to can matter more than one that reaches many thousands elsewhere, which is why the demographic breakdown next to the count is often the more useful part of the page.