It seems the idea is that it gets so big that it either can't exist without it or leeches the userbase. I've not really seen any explanation either, but I've come up with an idea around it. For example, in my experience Lemmy.World is filled with the type of people who would use Threads (from responses I've gotten about corporations like Spotify and Apple - heavily praised and no negativity about them). As threads and .world users interact, over time there becomes a dependency between those instances due to the community connections that are made. At a certain point, one or the other does something to encourage usage - that would be Extending.

For how long would something like activitypub be able to hold out? If Meta begins making contributions to it? Or if after that dependency, Meta makes a chance to how their federation works internally and fractures the point of activitypub by making instance runners/users pick one or the other. Or worse, Meta flat out buys Automatic. There goes the Fediverse.

FWIW - I'm not informed or have any idea what I'm talking about in this regard. I'm fully guessing and postulating, I don't even think I'm parroting what I've read somebody else say about it because, like I said, I've yet to see an explanation how the extinguish would function in this example. Historically I have an idea, but the circumstances here are different, ish.

But, this is Meta we're talking about. I don't think we'd be any happier federating with Reddit if the opportunity arose because these companies have historically shown they will pull teeth to get what they want, no matter how many people's teeth they have to pull.

"Well can they?"

I don't know. Maybe not? Do you want to let them try? Why let them? By defederating, it's like having a glass wall where yes, they can see everything looking in, but the interaction is mitigated. Ifnthe example I brought up is accurate, any changes .World decided to make with Meta in mind would not affect the rest of the instances that have defederated, since we don't even see that stuff from them in the first place.

Comparatively, slrpnk.net currently is federated with .World but not Threads, so if .World makes changes, those may be seen from instances that are federated with it?

From my understanding, a specific post on .World that has interaction from Threads and slrpnk.net. Threads and .World would see everything while Slrpnk.Net would only see federated instances and .World comments.

We are about 1.5m here in the Fediverse. Threads is already 100m. That's quite a large number of things to be missing, so it's possible that there's a large number of conversations that defederated users are only seeing half of? That could be another example that pushes Extinguish.

Anyway, sorry for any confusion or nonsense - I wrote this in a hurry on my phone, but I also wanted to lay out my thoughts and understand to see if it's at all in the ballpark. Shit, just use me as Cunningham's Law.