That needs a longer explanation.
An instance does not interact with all other instances. It only syncs with other instances when users follow someone there, join a community, …
But that’s also a problem. It means you can’t search the entire Fediverse from a particular instance and find new and interesting discussions and people. There is no discovery feed. For that, you need something like Bluesky’s relay. That relay actually does keep up with what everyone is posting and archives it.
But that’s one aspect of Bluesky that draws a lot of criticism by Fedi people. A full relay is expensive to run and not something anyone can self-host. Pruned down versions are doable, though. If everyone actually did run their own relay, then one would get you the combinatorial problem.
In practice, large instances are the Fediverse solution to the discovery problem. You can see what the many users on that instance post. Also, the many users subscribe to many things and so a large instance will cache much content from elsewhere. That architecture encourages centralization.
There’s other difficult issues. So you have a little server that serves your content to a few followers. Some celebrity with millions of followers would have to rent an entire server rack. But what if little old you interacts with a celeb and now all their followers try to fetch your content from your little server? Common problem. You just need caching. EG the celebrity rack also serves your content to their followers and takes the load off your server. But now whoever is doing the caching can also filter replies. There’s no simply solution there.
poVoq@slrpnk.net 3 weeks ago
Modern webservers don’t have a problem serving thousands of requests as long as they are spaced out a bit timewise. And since each AP instance only sees and interacts with a small part of the overall network it should not become an issue to expand the network horizontally. It is anyways probably better to think of interconected archipelagos and not of a singular network in the case of ActivityPub.
naught101@lemmy.world 3 weeks ago
Is that really true though? Say we end up with 10k servers with 100-1000 users each, even if only 10% of those users have a connection to a server that no one rose on their server is connected to, that’s still a highly connected network.
Then add boosts from other servers (that incentivise cross-network follows)…
poVoq@slrpnk.net 3 weeks ago
Mastodon already has those numbers you mention and there are no performance issues in the overall network.
naught101@lemmy.world 3 weeks ago
I don’t believe that’s true… It currently has around 9k servers, but I think the vast majority of those will have less than 10 users.
Anyway, there’s currently about 1m active users, so the real question is will it scale by 3 orders of magnitude? And my point being that I’d expect the network to become more connected as it scales (at least for the main archipelago, which is probably always going to house a majority of users).