Apple's iOS 27 shuts some web ads out of iPhones by blocking adtech domains inside WebKit

Apple's earlier privacy moves took away ways of recognising people. Intelligent Tracking Prevention, launched in 2017, limited cookie tracking across the web, and the industry answered with alternative identifiers built to work without cookies ^[9]. iOS 27 blocks those identifiers across browsers on Apple devices ^[1]. It also blocked calls to certain adtech domains outright, and on affected browsers some ads were not served at all unless the company found a workaround ^[3].

Relief has so far reached one company. Of the five firms whose domains were named in the block ^[8], The Trade Desk is the only one reported to have received a change from Apple ^[16]. That change is partial. The new beta separates The Trade Desk's ad-serving domain from the block on its Unified ID 2.0 identifier ^[4], while identifiers stay on the list ^[7]. Business Insider's report does not say whether ID5, LiveRamp, Permutive or Audigent have asked Apple for similar treatment.

Sequencing matters for anyone setting a holiday budget. Dustin Cha, co-CEO of Ad-Shield, said The Trade Desk's ad-serving domain stays blocked in practice until iOS 27.2 ships ^[5]. He said the timing "would likely put it in the second half of Q4" and "in time for the holiday season" ^[6]. If he is right, the block on The Trade Desk's ad server covers at least the first half of the quarter ^[17]. Next quarter brings a different risk. According to AdExchanger, Apple can update its wider block list without releasing a new version of iOS, and affected companies may not know they have been blocked until something stops working ^[12].

Tony Katsur, CEO of the IAB Tech Lab, said policing the internet should be up to governments. "When governments pass laws and regulations in the interest of consumer privacy, it applies them to all, and it's consistent across everyone," Katsur said ^[13]. "When a corporation like Apple pushes something like this out, it's uneven," he said ^[14]. Apple's long-held position is that privacy is "a fundamental human right" ^[15]. In my view the record so far fits both. Identifiers stay blocked, consistent with Apple's principle ^[7], and the unevenness Katsur describes shows in who has received a fix ^[16]. Mathieu Roche, CEO of ID5, told Business Insider: "It's getting more and more aggressive." ^[11]

Spending that leaves the open web goes somewhere. Business Insider says the change can push marketing money toward platforms with large stores of first-party data, and notes that Apple has a growing ad business ^[18]. For a CMO, the trade-off this quarter is between keeping iPhone web reach, at higher prices for the audiences still identifiable and with weaker measurement ^[19], and moving budget to those platforms. When Apple tightened tracking in apps, Meta said in 2022 that the App Tracking Transparency change could cost it $10 billion in revenue ^[10].