Apple is rolling out iOS 11 and macOS High Sierra today, bringing with them a new cookie anti-tracking feature in Safari that advertising groups say will "sabotage the economic model for the internet".
Globally, iOS is dwarfed by Android, but Safari accounts for a little under half of all mobile web traffic in North America and a quarter in Europe, according to StatCounter. And adoption of the newest version of iOS has historically been rapid compared with Android, so the impact of changes to how Safari handles cookies will be swift.
The system puts new restrictions on how cookies can be used to personalize ads. Safari already blocks third-party cookies, but ITP will delete first-party cookies too if the user hasn't interacted with the site in the past 30 days. It will allow cookies to be used in a third-party context for 24 hours to support login scenarios.
Apple says the intent is to ensure that users only have persistent cookies from sites they interact with while tracking data is continuously cleaned out.
The approach is different to Google's forthcoming ad-blocker in Chrome, which will target annoying and intrusive ads rather than online tracking.
The ad industry says Apple's ITP is placing a set of "haphazard rules over the use of first-party cookies" and asked Apple to "rethink" its approach to online privacy.
"Apple's unilateral and heavy-handed approach is bad for consumer choice and bad for the ad-supported online content and services consumers love," the advertising groups argued.
"Blocking cookies in this manner will drive a wedge between brands and their customers, and it will make advertising more generic and less timely and useful. Put simply, machine-driven cookie choices do not represent user choice; they represent browser-manufacturer choice."
The letter was signed by the American Association of Advertising Agencies, the American Advertising Federation, the Association of National Advertisers, the Data & Marketing Association, the Interactive Advertising Bureau, and the Network Advertising Initiative.
However, Apple has no plans to drop ITP from Safari, and in a statement on Friday reiterated its stance that users feel that trust is broken when their web activity is tracked online and sold for purposes they didn't agree to.
"Ad-tracking technology has become so pervasive that it is possible for ad-tracking companies to re-create the majority of a person's web browsing history. This information is collected without permission and is used for ad retargeting, which is how ads follow people around the internet," an Apple representative said.
"Apple believes that people have a right to privacy."