Reach

Reach counts the number of unique users who saw a piece of content, regardless of how many times each person saw it — distinct from impressions, which counts total views including repeats.

Reach is typically the more meaningful distribution metric of the two: it tells you how many distinct people the content reached, not just how many times it appeared. Reach is also the figure most platforms surface in business dashboards as "people reached".

Reach is bounded by the platform’s algorithmic decisions about who sees the post. Organic reach has trended down on most platforms over the past decade as feeds become more algorithm-curated and less chronological. Paid reach is unbounded except by budget; organic reach is bounded by algorithmic favor.

Reach is the cleanest measure of a post’s real distribution. A 10K-follower brand whose posts reach 2K people on average is in a different situation than one whose posts reach 8K, even if engagement rates look similar.