To minimize blowback, you need to show that you respect user's privacy:
- Communicate clearly and discuss openly before writing code, asking for feedback from the community.
- Make very clear from the beginning that this is opt-in (Audacity failed this, IMO)
- Give specific examples of the actual benefits of telemetry in concrete terms (e.g. "leverage with hardware vendors"), not just "make $product better".
- avoid dark patterns (the screenshot Audacity has added now to the pull request has a highlighted "yes" button - that already will make some people hate you, anything worse than that will rightfully make most privacy conscious people hate you)
- Avoid controversial third party providers (this likely amplified the outrage in the Audacity case a lot)
- If you screw up and/or get unlucky and a shitstorm starts, back down. Even if Audacity actually fixes the issues to a point where everyone would consider it reasonable had it been like that from the start, trust has been lost to the point where any telemetry feature will be controversial.
Audacity screwed up in multiple ways:
- poor communication in general
- Still doesn't intend to make the data collection opt-in. (The update check sends OS and version information, and that part is supposed to be opt-out.) The privacy policy also makes clear that it wasn't supposed to be opt-in (uses legitimate interest instead of consent, tells people who are under 13 to not use the app).
- introduced this shortly after other controversial changes (change of ownership, CLA requirement)
- collecting data "For legal enforcement"
- "If you are under 13 years old, please do not use the App." (following from COPPA limitations - it should be "please disable analytics" instead)
- used controversial third party providers