Apple is rolling out App Tracking Transparency (ATT) policy that will require developers ask permissions before apps can user their unique Identifier for Advertisers (IDFA) for third party ad tracking. Apple wants users aware of what data an app will track before installing, as well as gives users the choice to opt-out tracking.
To minimize the impact of any data loss, Facebook has created “Aggregated Event Measurement”, which would “help you measure campaign performance in a way that is consistent with consumers’ decisions about their data.”
On the other hand, Google has taken a different approach and switched to another Apple ad tracking tool: SKAdNetwork, which is considered less effective to let advertisers to track users.