Where is it stored if someone follows you? Is there some nice article that would explain where data is, how is it replicated and how queries are done?
Discussion
It’s stored on kind3 contact lists, so to count follows in-protocol you have to pull everyones contacts list who follows you which is an expensive operation. We don’t have COUNT in-protocol (yet) unfortunately.
If I understand correctly you need to check contact lists for all users on all relays to count it correctly? That would be indeed very expensive to do. Thanks!