Apple’s App Tracking Transparency feature will be enabled by default and arrive in ‘early spring’ on iOS

And here are the basics of what you need to know:

• The App Tracking Transparency feature moves from the old method where you had to opt-out of sharing your Identifier for Advertisers (IDFA) to an opt-in model. This means that every app will have to ask you up front whether it is ok for them to share your IDFA with third parties including networks or data brokers.
• The feature’s most prominent evidence is a notification on launch of a new app that will explain what the tracker will be used for and ask you to opt-in to it.
• You can now toggle IDFA sharing on a by-app basis at any time, where previously it was a single toggle. If you turn off the “Allow apps to request to track” setting altogether no apps can even ask you to use tracking.
• Apple will enforce this for all third-party data sources including data sharing agreements, but of course platforms can still use first party data for advertising as per their terms of service.
• Apple expects developers to understand whether APIs or SDKs that they use in their apps are serving user data up to brokers or other networks and to enable the notification if so.
• Apple will abide by the rules for its own apps as well and will present the dialog and follow the ‘allow apps to request’ toggle if its apps use tracking (most do not at this point).
• One important note here is that the Personalized Ads toggle is a separate setting that specifically allows or does not allow Apple itself to use its own first party data to serve you ads. So that is an additional layer of opt-out that affects Apple data only.

Apple is also increasing the capabilities of its Ad attribution API, allowing for better click measurement, measurement of video conversions and also — and this is a big one for some cases, app-to-web conversions.

This news comes on Data Privacy Day, with CEO Tim Cook speaking on the issue this morning at the Computers, Privacy and Data Protection conference in Brussels. The company is also sharing a new report showing that the average app has six third-party trackers.

While this seems like a welcome change from a privacy perspective, it’s drawn some criticism from the ad industry, with Facebook launching a PR campaign emphasizing the impact on small businesses, while also pointing to the change as “one of the more significant advertising headwinds” that it could face this year. Apple’s stance is that this provides a user-centric data privacy approach, rather than an advertiser-centric one.