Google Ads will change Demand Gen campaigns so Lookalike segments act as an audience suggestion by default instead of a strict targeting limit, letting its AI serve ads to people outside the lookalike group an advertiser picked. Lookalikes are built from an advertiser’s customer lists, YouTube audiences, app users, and site visitors, and cover the most similar 2.5%, 5%, or 10% of people in a location. Advertisers who want to keep that audience as a hard boundary have to opt out through a Google form, and Google hasn’t said when the new default kicks in or whether it applies to campaigns already running.
