You can find the total amount of "local" users on your #Mastodon instance on the /about/more page!
https://mstdn.social/about/more
On the homepage /about you can see the total "active" users!
#Mastodon is free open source software, this means that anyone can host their own server(instance).
On mstdn.social we run a little different source code than on most other Mastodon instances. We have the full features but also a little extra.. Details here: https://mstdn.social/about/more#features
You can find the Mastodon source code here: https://github.com/mastodon/mastodon
And the code we run is stored here: https://github.com/mstdn/Mastodon
Free for everyone to download and use! 
@stux aaa what a scammm
@kreyren That's up to you