Apple’s Privacy Preserving Ad Click Attribution in Safari

In a WebKit post today, Apple has an idea to make online ads private. It’s called Privacy Preserving Ad Click Attribution.

Private Ads

Ads can follow you around the web, tracking which sites you visit and collecting some of your data. You could use an adblocker, but that takes money away from the websites you visit. Whether we like it or not, most of the free content on the web is paid for with advertising. Privacy Preserving Ad Click Attribution has three steps:

1. Store ad clicks. This is done by the page hosting the ad at the time of an ad click.
2. Match conversions against stored ad clicks. This is done on the website the ad navigated to as a result of the click. Conversions do not have to happen right after a click and do not have to happen on the specific landing page, just the same website.
3. Send out ad click attribution data. This is done by the browser after a conversion matches an ad click.

I won’t go into the technical details here, but basically it makes sure ads can’t personally identify you. Ads can know that a person clicked on it and bought something, but they don’t know who. And these are first-party ads. Only the website whose ad you clicked on can measure this data. Third-party ads don’t get access to this.

Further, your browser—Safari in this case—can actually create a delay between the ad click and conversion at random by up to two days. This further de-identifies people because this data is sent through private browsing so it’s not associated with your other browsing.

Apple is offering Privacy Preserving Ad Click Attribution as an experimental feature starting with Safari Technology Preview 82, and it will be available in future versions too.

Further Reading:

[macOS Mojave: How to Reset the Mac Advertising Identifier]

[Apple Is Going to Sabotage the Internet, Says Advertisers]