cross-posted from: https://lemmy.world/post/855849
m/dance was created very recently on kbin.social and has only a few posts. Still, if I search for its URL on lemmy.world it is visible and I can subscribe, though I can’t see any of the posts: https://lemmy.world/c/dance@kbin.social
I recently created the community c/survey_polls on lemmy.world, but when I search for it on kbin.social it is not visible. I can see the cross-posts I made on c/general and c/newcommunities, and looking at my profile through kbin.social my first post to c/survey_polls also doesn’t seem to be visible.
My point is, what communities/posts are or aren’t visible across lemmy.world and kbin.social? Do posts from one website only appear on the other if the community already has subscribers? Or is there some sort of time threshold?
Yes.
When instances federate, they don’t just automatically share content. They only share the content from a specific community/magazine if somebody from the federated instance subscribes through that instance to the community/magazine on the host instance.
If I’m following it all correctly, what actually happens under the hood is that subscribing to a community/magazine on another instance triggers the creation of a new community/magazine on your home instance, which from then on will mirror the content on the original.
So in your example, the original is survey_polls@lemmy.world. Initially, it’s not going to appear on kbin.social - there has to be interest in it first, as demonstrated by the fact that somebody from kbin.social subscribes to it.
At that point, for all intents and purposes a new magazine is actually created on kbin.social - survey_polls@lemmy.world@kbin.social. So you’re not actually accessing survey_polls@lemmy.world through kbin.social - you’re accessing a mirror that’s hosted on kbin.social. And the trigger for creating that is someone on kbin.social subscribing to survey_polls@lemmy.world.
At least I’m pretty sure that’s how it works - note that I’m just some guy who likes to figure out how things work and not a dev.
So, if 10 different users subscribed to 10 different things all that data is now synced and hosted on their server of origin? That sounds like the data can get massive fast.