A pet store advertiser wants to increase the scale of its audience in a consideration campaign by finding people on Pinterest who behave similarly to those who have signed up for a newsletter on its website. Which audience is required to create an actalike?

To create an actalike audience (also known as a lookalike audience), Pinterest needs a source audience to model. A customer list, uploaded directly from the advertiser's newsletter sign-ups, provides the specific user data required to identify common characteristics and behaviors. Pinterest then finds other users who "act alike" based on these patterns, expanding the reach to a relevant, high-intent audience. Engagement audiences are based on Pinterest interactions (e.g., Pin saves), not external website actions. Expanded audiences broaden targeting but don't use a specific seed audience to find similar users. Website visitor audiences are based on general site visits, not a specific action like newsletter sign-ups, and while useful for retargeting, they aren't the direct source for creating an actalike of newsletter subscribers.