Fediverse

It's complicated.

You could federate with millions of instances if the people using them are not doing very much. But a handful of instances could theoretically overwhelm the whole network if they had malicious bots spamming like crazy.

The instance that hosts a community is responsible for sending copies of everything to all following instances, so most of the load is on those instances that host lots of popular communities. All other instances just need to be powerful enough to keep up with what they receive, which is 100x less work.

So even more important than spreading users out among instances, is spreading communities out among instances. Communities cause most of the load.

traffic volume is already a serious consideration, but theroetically its what you request. its not like an instance comes up and suddenly needs to interact with 500 other servers.

if you on your personal instance decide you need to subscribe to thousands of communities on thousands of servers... isnt that kinda on you? i mean.. how could you personally ever expect to consume that volume?

if youre on a community instance and the instance itself is drawing a metric fuckton of traffic.. scale up. the good platforms will scale.

that said, ive kinda tried to sub to every server i can find just for giggles... it 'pre-loads' the content on my instant for new users in the 'newest' queues.

there are mitigations you can put in place for rate-limiting other servers also.. your server would just fall farther and farther behind

personally, i think it scales better than other options. bluesky doesnt scale at all

In theory one day its going to be too much for our current bandwidth. We are no where near that even with single user instances.

There are ways of making things much more efficient. Piefed for example bundles up votes so the API doesn't get hit with millions of upvotes all separately. Peertube has P2P video sharing so the more people host/view videos, it actually gets faster. Theres a ton of others. But it sounds like a future issue.

I think there's a lot of nuance here. I mean the Fediverse isn't super efficient. But it manages to do what it's supposed to do. And it really depends. Which Fediverse software. How many people are on those servers, how are they distributed. Do groups of people mingle on certain servers. Do they all subscribe to all the same content out there. Are there really big groups on servers with happen to have a slow internet connection... And then of course can we come up with improvements if we need to.
I think we're going to find out once (or if) the Fediverse grows substantially. Some design decisions of the Fediverse are indeed a bit of a challenge for unlimited growth. Oftentimes technical challenges can be overcome, though. With clever solutions. Or things turn ot differently than we anticipated. So I don't think there's a good practical and straightforward answer to the question.