A nonprofit files a complaint against Mozilla for adding a post-cookie web tracking feature.
The nonprofit digital privacy group known as Noyb has filed a complaint against Mozilla on behalf of a user Wednesday over a Firefox feature dubbed Privacy-Preserving Attribution (PPA) that was added to the web browser back in July.
The feature is designed to help Firefox send data about user activity to advertisers in a way that doesn’t identify specific users, according to a post from Mozilla. The feature, which is included in Firefox 128 and newer, stores data on what site displayed a specific ad to a Firefox user. If the user engages with that ad, the website showing the ad can get Firefox to create a “report.”
While Mozilla doesn’t specify what data is included in the report, it says the report is generated “based on what the website asks.” So that could contain user data, the interaction data, and the ad data. But instead of handing that data over directly, Firefox mixes it with other similar reports and uses the mathematical technique of differential privacy.
Noyb takes issue with this feature because it is enabled by default, and Firefox didn’t explicitly warn users in advance about the feature before it was turned on. As Noyb points out, Mozilla tech lead Bas Shouten previously said the feature is opt-out (and not opt-in) because “Opt-in is only meaningful if users can make an informed decision.
