The gist of it seems to be that Mozilla and ISRG now proxy the tracking data and give aggregated reports to advertisers. And that they handle the data in a way

The gist of it seems to be that Mozilla and ISRG now proxy the tracking data and give aggregated reports to advertisers. And that they handle the data in a way so that neither Mozilla nor ISRG alone can access the unaggregated data. From reading around their documents ... https://blog.mozilla.org/en/mozilla/privacy-preserving-attribution-for-advertising/ https://github.com/mozilla/explainers/tree/main/ppa-experiment https://datatracker.ietf.org/doc/draft-ietf-ppm-dap/ ... it sounds a bit like they route the data through something like an onion network. So nodes in the network do not know what data they are routing and the advertisers get aggregated data without knowing who the users were: ... our DAP service, which is a Multiparty Compute (MPC) system based on Prio ... And the "Multiparty" seems to be these two: Our DAP deployment is jointly run by Mozilla and ISRG. Privacy is lost if the two organizations collude I think this is actually an interesting approach. I don't know whether two parties are enough and whether the specific algorithm used is good. But if it works as advertised (haha), it would result in measuring ad effectiveness without compromising user privacy. Which might be a good thing.