The act of pulling back users who churned (usually defined as inactive for 28+ days) so they re-engage, often tracked as its own cohort alongside new and active users.
Pinterest's growth team began reporting resurrected users as a third headline cohort in 2017, separate from new and existing actives. By 2019 the cohort topped 60 million monthly, driven by lifecycle email campaigns and targeted reactivation pushes. The framing changed how Pinterest's investors valued the business: a user lost was not a user gone forever.