What is Advertising ID?
A unique identifier assigned to your mobile device by the operating system, used by apps and advertisers to track your behavior across applications.
Every smartphone has an advertising ID — IDFA on iOS, GAID on Android — that enables cross-app tracking.
What It Enables
- Apps share your advertising ID with data brokers
- Data brokers combine data from multiple apps to build a profile
- Advertisers target you based on apps you use, places you visit, things you buy
- Your real identity can often be inferred from the behavioral data
How to Limit It
iOS:
- Settings > Privacy > Tracking > Disable "Allow Apps to Request to Track"
- This effectively zeros out your IDFA
Android:
- Settings > Privacy > Ads > Delete advertising ID
- On Android 12+, you can opt out entirely
Beyond the Advertising ID
Even with the advertising ID disabled, apps can use other signals to track you: IP address, WiFi network, device model, installed app list, and more. The advertising ID is just the easiest method.
Related Terms
Browser Fingerprinting
A tracking technique that collects information about your browser, device, and settings to create a unique identifier. Unlike cookies, fingerprints are nearly impossible to delete and can track you across websites without your knowledge or consent.
Third-Party Tracking
The practice of monitoring user behavior across multiple websites using embedded scripts, pixels, cookies, and fingerprinting techniques.
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