@ricci This is cool. I see the size difference as in mapping mastodon.social to the biggest city in the country I'm in maps what I think as big servers to what I wouldn't consider big enough to be a city, like districts of other cities. Both fedi and the country look too centralized, with software being optimized for huge instances and the central administration assuming everyone lives in the "default city".
(I've also learned the non-fedi fact that there is a city with the population of 307 people, less than a large apartment building.)