@freeschool I don't know, but let's start counting!
1, self hosted
Joking aside, according to the internet™, 1.5 billion people use gmail. Estimating that half the global population uses email in some form (source: made it up), this would leave about 2.5 billion unaccounted for. I am afraid a large percentage of those is on some flavour of Exchange while most of the rest are probably using something sensible or ProtonMail.
...?
@freeschool I don't know, but let's start counting!
1, self hosted
Joking aside, according to the internet™, 1.5 billion people use gmail. Estimating that half the global population uses email in some form (source: made it up), this would leave about 2.5 billion unaccounted for. I am afraid a large percentage of those is on some flavour of Exchange while most of the rest are probably using something sensible or ProtonMail.