Apple starts collecting Safari browsing data in macOS High Sierra using differential privacy tech that will help it identify problematic websites
Today's public release ofmacOS High Sierra brings with it some key updates to Safari — including the ability to disable cross-site cookie tracking and turn off autoplaying ads.
Context & Ripple Effects
High Sierra's public release completes what Apple previewed at WWDC in June, when it unveiled auto-play blocking and tracking protection in Safari. What's new today beyond those user-facing toggles is quieter: Safari now collects browsing data using differential privacy, letting Apple identify problematic websites while claiming no individual user's history is exposed.
The timing matters because Apple is fighting on two fronts at once. Weeks ago it defended Intelligent Tracking Prevention against criticism from ad groups, insisting it only blocks re-targeting and still allows cookies from sites users actually visit. Now it is simultaneously restricting ad networks' access to Safari users while expanding its own telemetry — under a privacy-preserving label.
First-order effects
- Safari users on High Sierra gain immediate toggles to disable cross-site cookie tracking and turn off autoplaying ads, shrinking the reach of third-party ad networks inside Apple's browser.
- Apple starts receiving differentially-private browsing signals it can use to flag problematic websites, giving it evidence to justify future blocking decisions without holding raw individual histories.
Second-order effects
- Ad groups that already attacked Intelligent Tracking Prevention gain a fresh grievance — Apple collecting browsing data itself while cutting off theirs — sharpening the measurement gap publishers see in Safari traffic.
- Rival browser makers are pushed down the same path: the corpus shows Google later committing to block third-party cookies in Chrome, and Apple escalating to a default full block of third-party cookies in Safari in 2020.
Third-order effects
- Privacy hardening becomes a compounding product strategy rather than a one-off setting — Apple extended the arc with limits on device fingerprinting in 2018 and a Safari Privacy button exposing how websites use data in 2020.
- If default tracking blocks spread across major browsers, the ad-tech ecosystem structurally shifts away from third-party identifiers toward first-party and contextual approaches, with browser vendors as the gatekeepers deciding what counts as acceptable.
The trend: Browser vendors are converting privacy from a settings panel into a competitive product feature, with Apple shipping tracking restrictions that pull rivals like Chrome into following suit.