Reach is the number of unique accounts or people who saw a post at least once during a given period.
What reach measures
Reach counts people, not views. If 500 people see a post, some of them twice, reach is 500 and impressions are higher. Reach answers "how far did this go?" rather than "how often was it shown?"
Reach can be broken down by source:
- Organic reach: people who saw it without paid promotion.
- Paid reach: people who saw it through ads.
- Follower versus non-follower reach: whether it spread beyond your audience.
Not every network reports reach, and not every API exposes it. When it is missing, impressions are the usual stand-in.
An example
Two posts each earn 2,000 impressions. One has reach of 1,900, so it was seen once by many people. The other has reach of 700, so a smaller group saw it repeatedly. The first spread; the second circulated.
Why it matters for AI-agent publishing
Cross-posting the same announcement to four networks multiplies reach only if the audiences differ. If an agent posts the same text to overlapping audiences, you add impressions without adding people.
SocialHandoff collects per-post metrics that each network returns and shows them through get_insights and an analytics card. Reach is shown only where a network supplies it. Pair it with engagement rate to judge whether a post both traveled and landed.