It's super useful in big companies. If you want head count, you gotta show numbers. Otherwise projects get canned. This is especially true for projects like the ones shown. Organizations want to know if people are actually using this stuff.

I disagree with the practice, but it's definitely the way it is.

Former Firefox dev here. I was part of the Firefox performance team, which introduced Telemetry in Firefox. We used Telemetry to measure the performance of many operations, to determine, among other things:

- which operations were running slowly on real user's computers (and how commonly they ran slowly), so that we could fix these;

- whether users were faced with out of memory errors, or timeouts, etc.;

- whether users had abnormally large database, preferences, etc. files, which suggested that we should optimize for such cases;

- in some cases, whether some features were used at all because if they weren't, it wasn't worth optimizing them.

I'd qualify these as definitely in the interest of the user.

I know that not everybody enjoys having Telemetry collected on their usage, but without this, Firefox would never have been able to catch up with Chrome on user-visible performance.

> - in some cases, whether some features were used at all because if they weren't, it wasn't worth optimizing them.

Terrible conclusion, by that reasoning a drunkard should only seek for his keys under the streetlight

https://en.wikipedia.org/wiki/Streetlight_effect

That’s good internetdebatesmanship, but if the post was “Firefox spent years optimizing thing no one ever uses at all”, it’s easy to imagine the ire that would raise for people who just wanted their keys not to be inexplicably lost under a streetlight.

Well, at some point, you have to make choices. If you don't have enough developers, you can either optimize features that users are using or features that users aren't using because they _might_ use them some day.

If you do the former, there is a chance you may be missing out. You do the latter, you are certain that you are missing out.

Not a browser dev, but not long ago I spotted a discussion of Chrome potentially deprecating/removing a rarely used XML API. The discussion was halted when a sudden spike in usage (IIRC, from well below 0.1% of whatever the metric to just slightly over 0.1%) was noticed. I have strong reason to believe I contributed to the spike (I was prototyping a change that hit it rapidly in the same time period), and I have strong reason to believe this particular API was preserved because telemetry was in place where a more conventional outcry would’ve been needed to otherwise stop the change (ahem alert ahem). But there wouldn’t be an outcry, the API is long standardized but basically unused outside of very odd corners of the web that aren’t very web centric.

I don’t want browsers or tools to undermine the trust of their users by quietly tracking unknown things. But I agree collecting usage data matters in ways that aren’t always appreciated.

I don’t know how to do it transparently and preserve/establish trust. But I think the instinct to distrust any metric collection probably isn’t the right balance to strike.

FWIW, the one feature that I had removed because nobody used it was the yellow bar in the bottom "Add-on foo is slowing down your Firefox, do you want to disable it?", so nothing quite standard :)

Dammit I was using that! ;)

But knowing which addons are slowing Firefox is quite useful, even if I decide to not disable the addon!

Yes, but I reimplemented the feature and moved it to about:performance.