# Lookalike Audience

> An ad-platform-modeled audience of new people who resemble a source audience, used to expand prospecting beyond your existing lists.

A **lookalike audience** is a segment of new people an ad platform models to resemble a source (or "seed") audience — for example, people who look like your past purchasers. It is how advertisers expand prospecting beyond their own lists, on Facebook (Lookalike Audience), Google (Similar Segments), and other platforms.

## Do not confuse with

- [Audience](/glossary/audience) — a lookalike is *modeled* by the ad platform from a seed; an audience is the segment *you* define from your own data.

## In AnyTrack

The quality of a lookalike depends on the quality of its seed. When AnyTrack sends conversions server-side with strong customer identifiers, the converter seed audience is cleaner and better-matched, so the platform-modeled lookalike is more accurate.