5 Years Of ATT: What We’ve Learned, And What The Future Of iOS Performance Looks Like
When Apple launched AppTrackingTransparency (ATT) in 2021, access to deterministic identifiers fell sharply as roughly 80% of users opted out of tracking. User-level feedback loops became sparse and biased, and iOS performance marketing shifted into a different measurement environment under SKAdNetwork (SKAN). Apple’s AdAttributionKit (AAK) later delayed postbacks, compressed conversion values and set privacy thresholds that made signal availability dependent on campaign structure and scale.