what if every police patrol car had a bank of cameras that scan not just every number plate but every face within a hundred yards against a national database of outstanding warrants? What if the cameras in the subway do that? All the connected cameras in the city? China is already trying to do this, and we seem to be pretty sure we don’t like that, but why? One could argue that there’s no difference in principle, only in scale, but a change in scale can itself be a change in principle.

Generative AI is now creating a lot of new examples of scale itself as a difference in principle. You could look the emergent abuse of AI image generators, shrug, and talk about Photoshop: there have been fake nudes on the web for as long as there’s been a web. But when high-school boys can load photos of 50 or 500 classmates into an ML model and generate thousands of such images (let’s not even think about video) on a home PC (or their phone), that does seem like an important change. Faking people’s voices has been possible for a long time, but it’s new and different that any idiot can do it themselves. People have always cheated at homework and exams, but the internet made it easy and now ChatGPT makes it (almost) free. Again, something that has always been theoretically possible on a small scale becomes practically possible on a massive scale, and that changes what it means.

This might be a genuinely new and bad thing that we don’t like at all; or, it may be new and we decide we don’t care; we may decide that it’s just a new (worse?) expression of an old thing we don’t worry about; and, it may be that this was indeed being done before, even at scale, but somehow doing it like this makes it different, or just makes us more aware that it’s being done at all. Cambridge Analytica was a hoax, but it catalysed awareness of issues that were real

The impact is particularly noticeable among Generation Z and millennials, the first generations to come of age with the possibility of knowing where their peers are at all times. It has changed how friends communicate with one another and blurred lines of privacy. Friends now, sometimes unwittingly yet obsessively, check one another’s locations and bypass whole conversations — about where somebody is, what they are doing or how their days are going — when socializing. All of that information can be gleaned from Find My.

Although Find My is not marketed as a social experience, sharing locations has become a test of sorts, much like being included on a close friends list on Instagram or on a private story on Snapchat can signal closer friendships.

With Find My, “you aren’t actively choosing to do something as you reach a certain location because you’re constantly sharing your location,” said Michael Saker, a senior lecturer in digital sociology at City, University of London. As a result, “there’s an intimacy that’s intertwined with that act,” he added. “There’s a verification of being friends.”

Advertisers don’t really want to know who you are - they want to show diaper ads to people who have babies, not to show them to people who don’t, and to have some sense of which ads drove half a million sales and which ads drove a million sales.

In practice, ‘showing car ads to people who read about cars’ led the adtech industry to build vast piles of semi-random personal data, aggregated, disaggregated, traded, passed around and sometimes just lost, partly because it could and partly because that appeared to be the only way to do it. After half a decade of backlash, there are now a bunch of projects trying to get to the same underlying advertiser aims - to show ads that are relevant, and get some measure of ad effectiveness - while keeping the private data private.

Apple has pursued a very clear theory that analysis and tracking is private if it happens on your device and is not private if leaves your device or happens in the cloud. Hence, it’s built a complex system of tracking and analysis on your iPhone, but is adamant that this is private because the data stays on the device. People have seemed to accept this (so far - or perhaps the just haven’t noticed it), but acting on the same theory Apple also created a CSAM scanning system that it thought was entirely private - ‘it only happens your device!’ - that created a huge privacy backlash, because a bunch of other people think that if your phone is scanning your photos, that isn’t ‘private’ at all. So is ‘on device’ private or not? What’s the rule? What if Apple tried the same model for ‘private’ ads in Safari? How will the public take FLoC? I don’t think we know.

On / off device is one test, but another and much broader is first party / third party: the idea it’s OK for a website to track what you do on that website but not OK for adtech companies to track you across many different websites. This is the core of the cookie question

At this point one answer is to cut across all these questions and say that what really matters is whether you disclose whatever you’re doing and get consent. Steve Jobs liked this argument. But in practice, as we've discovered, ‘get consent’ means endless cookie pop-ups full of endless incomprehensible questions that no normal consumer should be expected to understand, and that just train people to click ‘stop bothering me’. Meanwhile, Apple’s on-device tracking doesn't ask for permission, and opts you in by default, because, of course, Apple thinks that if it's on the device it's private. Perhaps ‘consent’ is not a complete solution after all.

If you can only analyse behaviour within one site but not across many sites, or make it much harder to do that, companies that have a big site where people spend lots of time have better targeting information and make more money from advertising. If you can only track behaviour across lots of different sites if you do it ‘privately’ on the device or in the browser, then the companies that control the device or the browser have much more control over that advertising