If data is migrated from server to server, as the community grows in size, the data to be maintained on each server also grows in size? Also i’ve seen some servers allow the creation of new users/communities, but some don’t… whats the point of that if the data is just replicated anyway?

If data is migrated from server to server, as the community grows in size, the data to be maintained on each server also grows in size? Also i’ve seen some servers allow the creation of new users/communities, but some don’t… whats the point of that if the data is just replicated anyway?