When discussing Fediverse, you sometimes hear the idea that you shouldn’t need different accounts for different platforms.
The “why can’t I comment under Youtube video with my Twitter account”.
In Fediverse it already works to some extent. You can comment under PeerTube video with your Mastodon account, and you can participate in Lemmy thread with your Mastodon account.
What is this functionality called? Does it have specific name?
It’s probably not “single sign-on” and not “federation” from what I understand.
And to what extent is it implemented? Is there some way to participate in Lemmy thread with your PeerTube account?
Is there any progress being made on implementing the initial idea of using any Fediverse account with any other Fediverse platform?
What is the name for the problem of implementing or mapping the platform-specific functionality? As in, neither Mastodon nor PeerTube have the interface for upvoting and downvoting posts.
Wouldn’t it be easiest to implement Fediverse-wide SSO (as in, log into Lemmy interface with your Mastodon account) instead of figuring out some funky mapping and patform interactions?
The fediverse is already, by itself, designed to be a framework for this exact thing.
The problems we have, and are always going to have, are that not all pieces of backend software have the same functionality. For example, you can already follow Lemmy communities and users from Mastodon, but not the other way round. If one backend implements some piece of functionality (e.g. upvoting/downvoting), then all backends that haven’t implemented it are going to be incomplete in how they can interact with it. It’s not possible to implement every conceivable functionality in all backends, that would actually kinda defeat the purpose of having different backends.
As for your idea of “fediverse-wide SSO”: there already is an open standard for SSO called OpenID. Fediverse instances could be OpenID providers if that’s desired. But that’s still a separate thing from ActivityPub.