At #RealWorldCrypto this year, there was a session on "privacy-enhancing technologies".

The first talk in the session was about a new encryption method for Tor.

The next two were painful examples of "a person cannot be convinced of something when their salary depends on them not knowing it".

Advertisers wants to collect signals about populations without being individually identifying. So let's talk about differential privacy techniques to let them do that.

One example was "Meta wants to know what percentage of its teneage users blocked a contact today".

At no point did they address the elephants in the room.

• Why do they want this data in the first place?
• What are they even doing with this signal?
• Have you considered telling them to fuck off and not collect it in the first place?

As tempting as it might be to hand wave it, and say "well yes but their business model depends on it", I say to advertisers, "then perish".