What is Reach?
Reach is the number of people that saw your ads. Reach is different to impressions, which includes multiple views of the same ad by the same person.
Why is Reach important?
Advertisers try to reach their target audience. They often use impressions to understand how often their ad was seen. This does not inform them how many people they reached. Instead, the Reach metric is better for this.
Reach is an important for upper-funnel marketing objectives, such as raising the awareness of the advertiser’s brand.