Glossary
What is limit ad tracking (LAT)?
Limit ad tracking is a device-level setting through which a user signals that they do not want interest-based advertising, restricting access to their advertising identifier.
How LAT worked
LAT predates ATT and worked on an opt-out basis: tracking was on by default, and a user who found the setting could switch it off.
When enabled, the advertising identifier was either zeroed or flagged, and advertisers were expected to honour the signal by not using it for interest-based targeting. Adoption was low, because the setting was buried and most users never knew it existed.
Why ATT superseded it
The difference between LAT and ATT is the default, and it turned out to be everything.
LAT required a user to go looking. ATT asks directly, in the moment, and requires an affirmative answer to proceed. The same underlying choice, presented differently, moved participation from a small minority opting out to a large majority declining.
That gap is the most instructive fact in the whole privacy transition: the technical capability barely changed, and the outcome changed completely. It is worth remembering whenever a consent mechanism is described as a formality.
Where the concept survives
Android retains an equivalent control — a user can delete their GAID, producing a zeroed identifier that functions as an opt-out signal.
Handling it correctly matters. Code that treats the zero string as a valid identifier will merge every opted-out user on the platform into one phantom device, which corrupts frequency capping, audience counts and attribution simultaneously. It is a common bug and an easy one to test for.
Common questions
Is LAT still relevant?
As a concept and on Android, yes. On iOS it has been effectively replaced by the ATT permission model, which asks rather than waits to be found.
Must I honour a LAT signal?
Yes — both platform policy and, in most jurisdictions, data protection law require it. Ignoring it risks app removal as well as regulatory exposure.
More in privacy and compliance
The identifiers, consent signals and rules that bound targeting.