The Fediverse works based on protocols which include ActivityPub and OStatus, which allow these instances to interact. Any time a user on 1 occasion posts a message, followers from every other occasion can see, reply to, and share this message. This interoperability represents a change to a more open up, https://econopass.com/news/world/is-the-fediverse-a-threat-to-centralized-social-media-platforms/