Catalin Cimpanu's 22-Aug-2017 bleepingcomputer thread Mozilla Testing New Default Opt-Out Setting for Firefox Telemetry Collection might be of interest to Firefox users who don't check their data collection settings at Options | Advanced | Data Choices on a regular basis.
Instead of having users opt in to allow Mozilla to collect detailed telemetry (e.g., top sites a user visits and how their browser features perform on specific sites) they'd like to switch to a new model where collection of detailed telemetry is enabled by default and users must opt out. I haven't read the entire discussion in the Google Groups thread Usage of Differential Privacy & RAPPOR but it sounds like they're going to run a small scale Shield Study with a group of randomly selected users in mid-September 2017 to get their feedback.
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32-bit Vista Home Premium SP2 * Firefox ESR v52.3.0 * NS v22.10.0.85 * MB Premium v3.1.2