Is it any service that includes the ability to federate? If so, are Matrix/XMPP/other non-ActivityPub services part of the Fediverse, or does Fediverse really just mean ActivityPub?
The context is wanting to promote a Matrix chat room on discuss.online: #online.discuss:discuss.online (see post). Does it belong in Lemmy communities like this one, !fedigrow@lemm.ee, etc? Or does it not count as part of the Fediverse?
Matrix and XMPP are federated but not part of the Fediverse, which revolves around ActivityPub. While they share the principle of decentralization, the Fediverse specifically connects platforms like Mastodon or Lemmy via ActivityPub. Promoting a Matrix room in Lemmy communities might align with shared values but doesn’t make Matrix part of the Fediverse. Bridging these ecosystems is possible but not inherent.