@freemo or anyone: I'm trying to find out how connected the graph of fediverse nodes is. For instance, if it's fully connected (every node connected to every other), that might imply a scalability limit to the number of nodes.
I guess another way of framing the question is whether two nodes A and B are necessarily directly connected because a user in node A follows a user in node B.
@underlap
The main problem to answer that question is to obtain the graph... I'm guessing that by node you mean instances, so you'd need to know which instances federate with which other instances... And there's no way to do that exactly.
If you had the graph, though, you'd want to look at the strongly/weakly connected components.
On the other hand, I'm not sure what you mean by scalability limit so can't help you with that.
@freemo
By scalability limit I mean some practical limit on the number of instances and/or users. It's looking like there really are no such limits unless we end up with some kind of uber instances with millions of users, which might then need to connect to hundreds of thousands of other instances (in a fictional future when the fediverse has taken over from traditional social media ;-) ).
@underlap
OK, I think I see what you mean... I'm not sure that this would be an issue if we move to multicast for broadcast but it may be a problem for a big instance that may need to handle several millions incoming messages from other instances... Maybe that will help ensure that we stick to instances with circa 1k users (in which case we would still need on the order of a million servers, but they would probably be unlikely to all federate due to language and topic preferences)
@freemo