Summary of my reply:

- Telemetry does not collect privacy-sensitive data

- You do not have to trust us, you can verify what data Telemetry is collecting in Firefox’s about:telemetry page and in aggregate form in our Telemetry dashboards

- Telemetry is an opt-in feature on release channels and a feature you can easily disable on other channels

- The new Telemetry clientID does not track users, it tracks Telemetry performance & feature-usage metrics across sessions

Hi Wladimir,

My name is Vladan, I am a member of the Firefox Performance team that works on Telemetry. I wanted to clear up a few points about Telemetry.

1) First off, Telemetry does NOT collect privacy-sensitive information about your browsing. And it NEVER will.

Telemetry does not collect URLs, nor IPs, nor search queries, nor locations, nor the websites you visited. We do NOT want to collect any privacy-sensitive data.

Examples of data we do collect:

- Performance data: how long it took your Firefox to start up, the animation smoothness of the tab-open animation

- Feature usage: whether you have enabled Electrolysis or not (Electrolysis is multi-process firefox)

- Hardware configuration: the number of cores your CPU has, the GPU your computer has, etc

This information helps my team understand how well Firefox is performing on different systems and which performance fixes to prioritize. It also helps other teams understand how well their features are working, and which Firefox features are popular with our users and which are not.

2) You do not have to trust us blindly with your Telemetry data! We show you all the measurements we are collecting.

If you have enabled Telemetry, just go to about:telemetry and you’ll see all the metrics we are reporting.

If you want to see that data in aggregate form for the entire Firefox Telemetry population, we built public dashboards and put the aggregated data on http://telemetry.mozilla.org/

3) Telemetry is an opt-in feature. Telemetry reporting is only on by default if you’ve installed a pre-release (e.g. beta) version of Firefox.

We understand many users are not comfortable sending performance and feature-usage data to Mozilla, and that’s fine. So we leave it disabled by default on the versions of Firefox used by the general public.

Telemetry is enabled by default on our Beta, Aurora and Nightly channels because these are pre-release builds and these users have gone out of their way to install a pre-release version of Firefox to get the latest features and help us test it out. These users are also generally more tech-savvy.

4) Everyone at Mozilla cares about user privacy.

You can see Mozilla’s stance on privacy here: http://blog.mozilla.org/privacy/2014/11/11/mozillas-data-privacy-principles-revisited/

I don’t think it’s fair to say Roberto was showing a lack of concern for user privacy in his blog post. He was excited about a new way to remove biases from Telemetry data so he wrote a quick blog post about it for other developers & statisticians.

—-

With regards to the UUID we added to Telemetry in bug 1064333:

- This is a randomly-generated UUID tied to a Firefox profile

- You will always be anonymous. The UUID does NOT correspond to an individual or even a computer, it only tracks the Firefox installation. I have over 30 different Telemetry UUIDs on my work laptop because I use different Firefox profiles for testing, and many more on my other computers. These UUIDs are not linked in any way

- The UUID is not used for tracking your behavior! The ID is associated with FHR & Telemetry metrics. We simply do not collect data about your browsing behavior because it would be a privacy violation.

- The client ID is used to correct reporting biases in Telemetry data. As Roberto explained, if we only know about Firefox sessions and not Firefox installations, then Telemetry data from short/frequent sessions is over-represented compared to Telemetry data from very long sessions

In summary:

- Telemetry does not collect privacy-sensitive data

- You do not have to trust us, you can verify what data Telemetry is collecting in the about:telemetry page in your browser and in aggregate form in our Telemetry dashboards

- Telemetry is an opt-in feature on release channels and a feature you can easily disable on other channels

- The new Telemetry clientID does not track users, it tracks Telemetry performance & feature-usage metrics across sessions