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, [email protected], etc? Or does it not count as part of the Fediverse?
I've been following this scene for many years, back when diaspora and friendica had a reasonable shot at promoting their own protocols rather than (what would become) ActivityPub — XMPP was still on the table as a possible avenue, as well.
There were lots of projects and developers pulling towards a general, shared goal — decentralisation — but with different code bases (ah, and did they want a distributed network or a federated one? Semantics like that ate almost as much time as agreeing on shared protocols). It was by no means a given that StatusNet would evolve via PumpIO into ActivityPub.
All I'm saying is, yes, ActivityPub is definitely the de facto protocol by now, but rather than look at this from a technology POV, I think it is worth taking a broader perspective of utility.
The Fediverse is, by that definition, a network of federated and interoperable server instances. As is pointed out, Matrix and XMPP are federated protocols, just not federating with the larger AP network. Heck, even Signal used to federate before Whisper closed its server off.
Federated chat is pretty much e2e-encrypted by default — I don't know that that has been successfully implemented in AP yet. In that regard, the fediverse is more fragmented than it needs to be.
Defining the fediverse around ActivityPub rather than the broader goal of federation and interoperability, we may lose sight of projects that are developed outside of the W3C, and might be the future of the fediverse.