Here are some early 2017 stats on where our users are:
https://pascalc.net/nightly_workshop_paris/#/3/1

As the link on arewestableyet indicates (although it is not very accurate), we are in the 10s of thousands range. In the ideal world I dream of, we would hundreds of thousands of Nightly users

That said, if we could just get closer to 100,000 that would already be a major achievement because the population that uses nightly are power-users they are not (and shouldn’t be) the general public.

Qualitatively, as you can see on the slide above, unlike Release, we don’t have nightly users everywhere in the world which means that we don’t have a good representation of the web and usage in many locations.