I recently subscribed to pensandpaper@lemmy.ml on kbin.social. I was the first person to do that as it was clear that the kbin copy was created with me clicking subscribe. It’s not a very active community with only two old posts but the only way to see those is by going to the original instance that it’s hosted on.
Is there a way to pull those two posts to the kbin version of that community? Or is it inherent to the Fediverse that things only start syncing with the first subscription on an instance and it’s not retroactive?
Let me know if there is a better place to ask this question.
In a word, no
This is accurate for the current state of lemmy/kbin, but there are ways it could be done. Mastodon made the decision to only fetch posts made after subscription/follow and all fediverse services have followed that pattern. But they don’t have to.
In ActivityPub, Actors (users and communities) have an outbox property. Any public post that actor makes should be available in that outbox. So when a user follows a user or community, their server could request a page by default, which wouldn’t be too much data, and present a Previous button in the UI that would fetch another page on demand. Since this would be a user interaction, it would happen later than the original follow and outbox request and would keep the requests spaced out so it doesn’t overload a server.