Correct!

Other than that there is no need to collect much other information at all.

Google Analytics is currently how I see how users found DarwinMail & where they came from.

Google Analytics also provides info such as users device and browser type.

A list of the data Google Analytics collects can be found here:

https://www.shivarweb.com/2977/what-does-google-analytics-do

Google Analytics is the defacto standard for millions of websites across the web.

Should probably mention that next you your statement about privacy. I would consider an email service that has Google analytics on it not terribly private

It is true that using Google Analytics does sound quite overt.

The question remains, how else can I see where my users are visiting from, what browsers & mobile devices are they using so that I may better tailor DarwinMail?

I would suggest one of the alternatives listed at https://switching.social/ethical-alternatives-to-google-anal... . Fathom in particular is open source and can be self hosted

Wow! Thank you for those suggestions.

I've looked into Fathom before. I quite like what's offered. And the fact that's it's open source is the cherry on top :)

Thank you very much for the suggestion and for giving me a direct link to check out more.

I've dropped Google Analytics in favor of good old fashioned server log parsing with several off the shelf tools.

The load times of my site, the quality of my stats and the privacy of my users have all been improved.

That's quite interesting. I like the sound of that. Thank you for your feedback.