Re-engagement in the era of privacy – the definitive guide

Apple's App Tracking Transparency (ATT) framework has fundamentally changed mobile re-engagement by limiting access to IDFA for personalized ads.
Marketers must shift from user-level data to aggregated data, relying on 1st-party data fortresses, audience segmentation, and owned channels like email and push notifications.
Key tactics include optimizing ATT prompt timing, using GBRAIDs for Google campaigns, and adopting incrementality measurement to assess true campaign impact.
While Android remains unaffected, iOS requires new approaches such as predictive analytics and top-down measurement.
The guide emphasizes diversification across paid, owned, and earned media, with a focus on contextual remarketing.
Despite challenges, re-engagement can boost retention by 85% (Android) and is cost-effective compared to UA.
The industry is in transition, with innovation gradually restoring measurability.