Fediverse

Also what’s rel=me?

It's just a semantic tag you add to a link on an IndieWeb profile (h-card) to indicate other addresses which describe the same person. So basically if lemmy implemented basic microformats2 (semantic classes for HTML, part of indieweb ecosystem), you could have an "alternative links" setting in your Lemmy profile that would link to your XMPP, email, mastodon or whatever other addresses. Ideally, we wouldn't even need so many accounts/addresses for a single identity, but as an intermediate measure a multi-protocol client (or a s2s bridge/gateway like bridgy could enable you to subscribe to one person's feed across all protocols.

The indieweb is based on a POSSE principle where your own website is the original source of truth for content but is socially-aware of both: what you republished elsewhere (eg. a twitter post) and replies coming in from elsewhere (eg. a reply on Lemmy). The rel=me link is one of the semantic foundations that enables this. That's just one approach to identity which places the web front and center, but we could also mention other approaches:

• domain name as identity (DNS, .onion)
• cryptographic keypair as identity (PGP, SSH, ZOT nomadic identities)

The rel=me specification addresses the "discoverability" problem. Both DNS and PGP can store arbitrary data and could be used to advertise different identities however i don't know of standard/specified ways to do it. Something else to consider about digital identities is that you sometimes want different inboxes (collections in ActivityPub parlance) under the same identity, like some people have bank@mydomain and ecommerce@mydomain email addresses. I think that's a rather compelling argument for domain name as identity but that's a complex topic with a lot of nuance (and it's not incompatible with backing your domain name with a cryptographic identifier like the GNU Name System does).

I'm happy to elaborate on certain points, or to provide detailed links (which i did not do in this reply sorry, but any web search engine should be able to help you out) if you ask for it :)