When users are on the web they can opt out of a lot of tracking present, thanks to a combination of GDPR-induced prompts, ad and trackers blocks, and incognito modes -- however, this is far from the case on mobile phones and apps.
In an effort to close the gap, Apple believes efforts like its Identifier For Advertisers can help advertisers and preserve privacy.
"Identifiers such as the Identifier For Advertisers (IDFA) and email address help identify a specific device across a network. They also allow advertisers to create a detailed profile of your activity across different apps or websites when they see your device identifier and associate your activity with it," Apple says in an updated version of its A Day in the Life of your Data document.
"The Identifier For Advertisers (IDFA) is a user-controllable identifier assigned by iOS to each device. As a software-based identifier rather than one that is tied to the hardware itself, the IDFA can be blocked for a particular app by the user via the App Tracking Transparency prompt. This gives the user control over IDFA-based tracking."
The updated document has added a pair of pages on advertising auctions and ad attribution, with Apple stating advertisers can track ad performance without tracking users. The mechanisms for this are its SKAdNetwork API and Private Click Measurement.
Pointing to the way web browsers have clamped down on trackers on the web, Apple has dismissed concerns that clamping down on trackers in apps will force app creation to be less profitable.
The tech giant believes advertisers will have to respond by providing users with a higher level of privacy and app makers will still be able to monetise from apps.
Apple said it would remove apps from its app store if a new way of fingerprinting was developed.
Last month, Apple claimed in Australia that its store was not the most dominant app marketplace because the internet was an alternative.
"Apple perceives and treats other distributors of apps, for platforms other than iOS, as significant competitors whose pricing and policies constrain Apple's ability to exercise power over developers," the iPhone maker said in a submission to the Australian Competition and Consumer Commission (ACCC).
"Apple is not in a position to disregard the environment in which its app marketplace operates and does not accept the Commission's characterisation of the Apple App Store as 'the most dominant app marketplace by a large margin'."
Apple said it does not consider it has a substantial degree of power in any market relevant to the issues that are the subject of the ACCC's current inquiry, nor does it agree there is a market failure that requires regulatory intervention or legal action.
"Apple faces competitive constraints from distribution alternatives within the iOS ecosystem (including developer websites and other outlets through which consumers may obtain third party apps and use them on their iOS devices) and outside iOS," it said.
"Even if a user only owns iOS-based devices, distribution is far from limited to the Apple App Store because developers have multiple alternative channels to reach that user.
"The whole web is available to them, and iOS devices have unrestricted and uncontrolled access to it. One common approach is for users to purchase and consume digital content or services on a website."
Days earlier, Apple said it was surprised to hear that developers have legitimate concerns about their ability to engage with Apple in the app review process.