It has come to my attention that many of the people complaining about #Firefox's #PPA experiment don't actually understand what PPA is, what it does, and what Firefox is trying to accomplish with it, so an explainer 🧵 is in order.
Targeted advertising sucks. It is invasive and privacy-violating, it enables populations to be manipulated by bad actors in democracy-endangering ways, and it doesn't actually sell products.
Nevertheless, commercial advertisers are addicted to the data they get from targeted advertising. They aren't going to stop using it until someone convinces them there's something else that will work better.
"Contextual advertising works better."
Yes, it does!
But, again, advertisers are addicted to the data, and contextual advertising provides much less data, so they don't trust it.
What PPA says is, "Suppose we give you anonymized, aggregated data about which of your ads on which sites resulted in sales or other significant commitments from users?"
The data that the browser collects under PPA are sent to a third-party (in Firefox's case, the third party is the same organization that runs Let's Encrypt; does anybody think they're not trustworthy?) and aggregated and anonymized there. Noise is introduced into the data to prevent de-anonymization.
This allows advertisers to "target" which sites they put their ads on. It doesn't allow them to target individuals.
In Days Of Yore, advertisers would do things like ask people to bring newspapers ads into the store or mention a certain phrase to get deals. These were for collecting conversion statistics on paper ads. Ditto for coupons.
PPA is a way to do this online.
Is there a potential for abuse? Sure, which is why the data need to be aggregated and anonymized by a trusted third party. If at some point they discover they're doing insufficient aggregation or anonymization, then they can fix that all in one place.
And if the work they're doing is transparent, as compared to the entirely opaque adtech industry, the entire internet can weigh in on any bugs in their algorithms.
Is this a utopia? No.
Would it be better than what we have now? Indisputably.
Is there a clear path right now to anything better? Not that I can see.
We can keep fighting for something better while still accepting this as an improvement over what we have now.
There is no such thing as "fully anonymised data". Data can be de-anonymised by anyone who aggregates it. It's been demonstrated over and over and over again.
And because of that, the advertisers are not the ones aggregating it
This is just false, there is a mathematical framework for aggregating data in a way that prevents de-anonymization https://en.m.wikipedia.org/wiki/Differential_privacy. This is what the US census department uses to release census statistics without impacting anyone’s privacy.
Whoever reports this "anonymized" data still knows something about you, whether that's a census employee at your physical house, or a website having your IP address. We can't stop that information falling into the wrong hands. Bad actors are everywhere. All we can do is not provide the information in the first place.