Reference / Glossary / Infrastructure and standards
Mobile Advertising ID
Also: MAID; IDFA; GAID; AAID
The resettable identifier a mobile operating system assigns to a device for advertising: IDFA on iOS, GAID (Google Advertising ID) on Android. MAIDs are the in-app equivalent of the cookie. Apple's App Tracking Transparency made the IDFA opt-in in 2021, and most users decline; Google has proposed and delayed equivalent limits under its Privacy Sandbox for Android.
Cite this entry:
Agency Echelon. "Mobile Advertising ID." Agency Echelon Reference, reviewed September 2026. https://agencyechelon.com/reference/glossary/mobile-advertising-id/