Apple starts blocking all third-party cookies in Safari

The new versions of Safari in iOS and iPadOS 13.4 and Safari 13.1 on macOS, will block all third-party cookies by default, Apple’s WebKit team this week announced.

John Wilander, WebKit Security & Privacy Engineer at Apple, wrote that this is a significant improvement for privacy since it removes any sense of exceptions.

1 year ago, Tune said client-side tracking is now dead. In 2019, this forced Google to rethink the audience creation, frequency cap, and measurement.

Apple first release against third-party cookies started in 2017, with the release of ITP, Apple’s Intelligent Tracking Prevention, a purge of all third-party cookies with over 1 day. ITP keeps working to detect bounce trackers, tracker collusion, and link decoration tracking, wrote John Wilander.

Apple says that is supporting cross-site integration via the Storage Access API, created two years ago, to provide the means for authenticated embeds to get cookie access with mandatory user control.

Apple wants to brand Safari as the privacy browser for the web, being the first mainstream browser to fully block third-party cookies by default. Google is expecting to follow the block of all third-party cookies by 2022.

Last year, Apple listed the “unintended impact” of blocking third-party cookies:

• Funding websites using targeted or personalized advertising
• Measuring the effectiveness of advertising.
• Federated login using a third-party login provider.
• Single sign-on to multiple websites controlled by the same organization.
• Embedded media that uses the user’s identity to respect their preferences.
• “Like” buttons, federated comments, or other social widgets.
• Fraud prevention.
• Bot detection.
• Improving the security of client authentication.
• Analytics in the scope of a single website.
• Audience measurement.

Another consequence is the rise of walled gardens, like Apple News,  YouTube, and Google Search. Seb Joseph wrote at Digiday that in the absence of third-party cookies, publishers are building walled gardens of their own.  In Germany, last year, SevenOne Media and IP Deutschland joined forces to sell addressable TV and online video via Active Agent.