Much more interesting, though, is what happens if Apple opens up its cohort tracking and targeting, and says that apps, or Safari, can now serve anonymous, targeted, private ads without the publisher or developer knowing the targeting data. It could create an API to serve those ads in Safari and in apps, without the publisher knowing what the cohort was or even without knowing what the ad was. What if Apple offered that, and described it as a truly ‘private, personalised’ ad model, on a platform with at least 60% of US mobile traffic, and over a billion global usersI don't understand how this works. How can publishers target ads without knowing what the cohort is?