Lookalike Audience is a modeled audience that resembles an existing customer, lead, or high-value audience.
It matters because most visitors do not convert on the first visit. Retargeting terminology helps teams create thoughtful follow-up sequences, avoid wasted impressions, and respect audience exclusions and privacy expectations.
Example
Where a platform offers lookalike modeling, an advertiser can supply an eligible customer audience as a source. The resulting audience contains people with modeled similarities, not people who have already visited the website.