Dumb question that I was always too afraid to ask:
I know how the #Fediverse and its federation works. It's intuitive and familiar to me; I mean, I even host my own instance.
But I never understood how interaction cross-software is supposed to work. In theory, I can use whatever #ActivityPub software I want and still interact with everyone else. But in practice that just... isn't the case, right?
I mean, for text it's quite simple: I write a short post on #Mastodon and people on #GoToSocial or #Misskey or whatever can see and read that same post and interact with it. They can see my profile and it appears on their instance in their style and with their features.
Even outside of microblogging I still get it. A super-long post on #Friendica or #Diaspora appears on my timeline, too. Their profiles might have more fields than I can see here, but that's fine.
But what's up beyond that?
I can see #Pixelfed posts here, converted into image galleries. But what about the other way 'round? If someone on Pixelfed follows my Mastodon account, they can't see any of my non-image posts, right?
What about #PeerTube and such niche software? I guess I could follow a PeerTube account as a microblogger and see their videos and descriptions in my timeline. Video comments are replies.
But the other way 'round? How are they supposed to interact with Friendica or Pixelfed users? PeerTube doesn't even have a "timeline".
Doesn't that feature disparity undermine the whole idea of the #Fediverse or am I missing something?