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What is an IDFA

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IDFA is the initial for Identifier For Advertisers. This is the only one of its kind identifier given to every smartphone operating under Apple’sApple’s iOS operating system. The IDFA is an identifier given randomly by iOS for each device and which is distinct from the serial number of the device given to it by the manufacturer (often also Apple).

What is IDFA? What exactly is it, and what is it for?
IDFA stands for “Identifier for advertisers”, it is a series of letters and numbers unique to each iOS device. IDFA is Apple’sApple’s standard for mobile ad networks to track users and deliver targeted ads to them. The same is true for ad apps, their ad partners, and their attribution partners.

Although UDID was very useful for ad tracking and authentication across multiple apps, third-party app software began to collect these UDIDs in databases and sometimes even sell them. The US Congress ultimately ruled that this violated a person’s right to privacy, and Apple had to restrict access to the device UDID for apps. To replace the UDID, Apple created the IDFA. Users can now turn off or reset access to their IDFA, while the UDID was a permanent device serial number, and once shared, there was no going back. With these changes, users have more control over their data and their privacy.

Prior to iOS 14, advertisers measured the effectiveness of their ads by using IDFA to identify a consumer who clicks on an ad and a consumer who downloaded an app, which allowed advertisers to better optimize their campaigns. Here is a typical example of how it works:

An app displays an advertisement with an embedded link. The link can either come directly from an advertising network or from a mobile measurement provider (MMP) acting on behalf of the advertising network. The URL link contains a parameter associated with the IDFA.

The user clicks on the advertisement. This triggers a network request (usually a chain of redirects routed through the user’s browser, but not always) in which the ad network / MMP collects the IDFA before redirecting the user to the App Store.

After the download is complete, the Ad Network / MMP SDK collects the IDFA again and combines the two values ​​to perform attribution.

What is the idea used for in the industry?
Users cannot directly access their IDFA on their Apple device; they must go through a third-party app. They can also choose to enable the Limited Ad Tracking option, a feature created by Apple to improve user privacy. Prior to iOS 10, if Limited Ad Tracking was enabled, a user’ IDFA was still accessible and could be used for certain purposes, such as attribution. Apple then toughened its policy with iOS 10, so users who turn on Limited Ad Tracking can hide their IDFA from advertisers and prevent tracking or attribution. Their IDFA is then replaced by a non-unique value composed only of zeros. Note that enabling Limited Ad Tracking does not miraculously make all ads disappear; it only prevents users from seeing targeted ads based on their interests and behaviours.

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