Apple iOS Update: Safari Ad Blocking

By the FAST team

Share on Facebook


Apple is limiting ad tracking on its Safari browser by replacing user cookie preferences with a set of Apple-controlled standards. The feature, which is called “Intelligent Tracking Prevention,” limits how advertisers and websites can track users by putting in place a 24-hour limit on ad retargeting.

Details and Implications:
iOS 11 was made available on mobile devices from Tuesday 19th September and the new Safari function will become available for desktop devices from 25th September as part of the High Sierra update to macOS. Safari is used by 14.9% of all Internet users, according to data from StatCounter (5.5% on desktop and 18.7% on mobile respectively).

Intelligent Tracking Prevention uses a machine-learning model to identify which sites a user is interested in and therefore which cookies it allows to track the user.  As an example: Say Intelligent Tracking Prevention classifies as being allowed to track the user as the user has visited the site. can then use that cookie to retarget the user in a third party context. However, after 24 hours the cookie cannot be used to retarget the user in a third party context unless the user revisits again. After 30 days, the cookie is purged entirely from Safari.

This provides an advantage to sites visited regularly when it comes to their ability to carry out third party tracking – think Facebook and Google where you log in daily – and a disadvantage to those who may want to target occasional visitors – like those who may be shopping for a new car or credit card etc. This is mainly a problem for desktop based browsing, as in-app ads do not use cookies, instead they use DeviceID as a common identifier. There have also been rumours, but no confirmation, that Apple intends all mobile-based tracking (even mobile web) to be Device ID orientated.

In response to the move, six trade groups – the Interactive Advertising Bureau, American Advertising Federation, the Association of National Advertisers, the 4A’s and two others – say they’re “deeply concerned” with Apple’s plans. Read their open letter published in AdWeek in the link below.

At the same time, Google is also taking measures to limit the ‘intrusiveness’ of advertising. It stated in a blog post on 14 September that starting in Chrome 64 (which is due in January 2018), autoplay video will only be allowed when either the media won’t play sound, or the user has indicated an interest in the media.

Safari third party cookie deletion will spur on innovation in digital ad tracking – the threat of losing cookies raises its head every so often and the industry will need to start heavily investing in new methods of delivering high quality user targeting without cookies.

Read it on

Further Reading:
Google Chrome Blog / The Guardian / Open Letter to Apple / Intelligent Tracking Prevention