⁨Apple explains why Safari now blocks email-based ad identity firms⁩.

⁨Apple has finally explained why Safari started cutting off some of the advertising industry's best-known identity companies last month. In a WebKit blog post published on 19 October, three of its engineers said the block targets "identity resolution": third parties that sit unseen on web pages, pick up a person's email address when they log in or sign up for a newsletter, and turn it into a tracking ID.⁩

⁨The post names no companies. But Digiday's reporting says LiveRamp, ID5, The Trade Desk's UID 2.0, Permutive and Audigent were among the first cut off when the update arrived in September, and the method Apple describes matches how those identifiers work.⁩

⁨What Apple says it is blocking⁩

⁨Apple's argument is that email addresses have replaced cookies as the thing cross-site tracking depends on. It blocked cross-site cookies six years ago; since then, it says, the industry has moved to email-based IDs that are harder to escape, because most people keep one address for years and use it on every device.⁩

⁨The key points from the post:⁩

• ⁨Third parties collect the email address, send it to their servers, create an ID permanently linked to it and pass that ID back to the website.⁩
• ⁨Logging out or unsubscribing doesn't remove the ID or the stored address.⁩
• ⁨Over time these firms build what the industry calls an identity graph, which Apple says enables cross-site and cross-device tracking.⁩
• ⁨In the version 27 releases of iOS, iPadOS, macOS and visionOS, Safari and WebKit block network access to this infrastructure at domain level, so changing how a request is built won't get around it.⁩
• ⁨First-party personalisation is not the target. But Apple says a central third-party resolver still links people across sites even when each client only shares its own customer data.⁩

⁨Apple also points users to Hide My Email, the iCloud+ feature that gives each website a random address.⁩

⁨What Apple left unanswered⁩

⁨The post doesn't say how a company ends up on the blocklist, how it might get off it, or which of the vendors publishers rely on fall on the wrong side of the line. That matters, because Digiday reports the list has already caught at least one company by mistake: The Trade Desk's ad server was blocked alongside UID 2.0 in the first days of the update and has since been switched back on, according to a person with knowledge of the matter.⁩

⁨For now the reach is limited. Digiday's own tests found most ad tech addresses it checked were still loading on updated devices. Apple's closing line, though, says it will keep blocking covert and cross-site tracking by default, which reads as a promise to widen the net.⁩

⁨The ads business in the background⁩

⁨Some in the industry will see a commercial motive, and Digiday sets out why. When Safari's Intelligent Tracking Prevention began stripping ad tech cookies in 2017, Criteo warned investors of a hit of up to 10% to fourth-quarter revenue ex-TAC. After App Tracking Transparency in 2021, Meta put its cost at around $10 billion for 2022, while Apple's share of the iPhone app-install ad market rose from 17% to 58%, according to Branch data reported by the Financial Times.⁩

⁨This time the block lands as Apple Ads is expanding into Maps and hiring. Digiday counted 86 open roles tagged Apple Ads, 17 of them in New York, including AI and machine-learning posts for ad matching and campaign optimisation. Apple pointed to its blog post and declined to comment further.⁩

⁨What it means for marketers⁩

⁨The direct effect is narrow but real: on updated Apple devices, email-based IDs from blocked vendors stop working in Safari, so reach, frequency capping and measurement built on them will weaken there. Marketers should ask their DSPs and data partners which of their identifiers are affected and what share of their audience is on Safari.⁩

• ⁨Audit any campaign that relies on a third-party email ID for targeting or measurement on the open web.⁩
• ⁨Lean on first-party relationships that run inside your own site or app, which Apple says it does not object to.⁩
• ⁨Expect more blocks, and plan measurement that doesn't depend on a single identifier.⁩

⁨No figures have been published for Saudi Arabia or the Gulf, so the regional impact is unknown. Brands and publishers here should pull their own Safari share from site analytics before deciding how much it matters, and ask agencies whether any Gulf campaigns lean on the blocked identifiers.⁩

⁨Sources⁩

• ⁨WebKit, "Blocking Identity Resolution Infrastructure", 19 October 2026⁩
• ⁨Digiday, "Apple finally explains its Safari block, and identity companies are in its sights", 20 October 2026⁩