From the Wikipedia article on cookies [1]: > Apple uses a tracking technique called "identifier for advertisers" (IDFA). This technique assigns a unique identi

From the Wikipedia article on cookies [1]: > Apple uses a tracking technique called "identifier for advertisers" (IDFA). This technique assigns a unique identifier to every user who buys an Apple iOS device (such as an iPhone or iPad). This identifier is then used by Apple's advertising network, iAd, to determine the ads that individuals are viewing and responding to. See Apple Advertising & Privacy [2] for details: > To see this information on your iOS or iPadOS device, go to Settings > Privacy > Apple Advertising and tap View Ad Targeting Information. On Mac, go to System Preferences > Security & Privacy > Privacy, select Apple Advertising, then click View Ad Information. [1] https://en.wikipedia.org/wiki/HTTP_cookie#Identifier_for_advertisers https://en.wikipedia.org/wiki/HTTP_cookie#Identifier_for_adv... [2] https://support.apple.com/en-us/HT205223 https://support.apple.com/en-us/HT205223