Reach
Reach is the number of distinct people who saw a message at least once in a given period. It counts people rather than views, so a hundred impressions on one person is a reach of one.
Reach, impressions and frequency
Impressions count every time the message was shown. Reach counts how many different people were behind those impressions. Frequency is the ratio, impressions divided by reach, and it says how often the average person saw the message. Advertising platforms report the three together because any one of them alone misleads: a large impression count with a small reach means the same few people saw it many times.
Reach in an AI answer
An assistant writes one answer to one person, and no assistant publishes how many people were told a given business’s name. Reach, in that channel, cannot be observed from outside. What can be observed is the other side: of the questions a business’s buyers ask, in what share of them is it named, and where in the answer. That is a mention rate, and set against the other businesses named it is a share of voice. This site reports those rather than a reach estimate, because a reach estimate would be a number nobody measured. The methodology page describes the panel.
A common question
Can reach be measured for a business that gets named in AI answers?
Not from outside. An assistant writes one answer to one person, and none of them publish how many people were told a given business's name, so the count of distinct people reached in that channel cannot be observed. What can be observed is the other side of it: across the questions a business's buyers ask, how often the business is named and where it sits in the answer. That is a mention rate, which this site reports with the other names given beside it, rather than an estimate nobody measured.