What it means for your advertising
You give the platform a source, such as a customer list or people who visited your website, and it finds others with similar characteristics and behaviour. On Facebook and Instagram you choose how close the match is, from a small, very similar group to a larger, looser one.
It's one of the ways audience targeting works on Meta, next to interests and remarketing. Remarketing reaches the people who already know you; a lookalike reaches new people like them.
Lookalikes are only as good as their source: a few hundred real customers says more than thousands of casual visitors. A customer list must be shared lawfully, with the right privacy notice in place.
An example
Java Roasters shares a list of its 400 subscription customers. Meta builds a lookalike audience of UK coffee drinkers who behave like them, people who have never visited the website.
Java Roasters is a fictional business, and its figures are illustrative.
How we handle it
Our team sets up lookalike audiences on Facebook and Instagram when your campaign has a good source to build from, and tells you what that needs. Our privacy guide covers sharing a customer list safely, and Facebook & Instagram advertising covers the rest of the targeting.