Some people love saying Mastodon/OStatus is very scalable because of federation but let's be honest that's some bullshit. It's easy to split and multiply, but that's not scaling.
The birdsite is much easier to scale.
Just imagine one edge case we're not seeing for now: many people using it (let's say millions) and following a very famous person
That person must have their own instance at this point, at least.
... what happens when they toot?
just imagine the enormous peaks and lag it'll do. And we're not even talking about media.
How would Mastodon realistically handle Katy Perry? I have no idea.
@CobaltVelvet I haven't looked into how OStatus/PubSubHubbub/whatever else is involved do this at the moment, but I can see a few ways to do this at scale. The celebrity instance would only have to contact each instance it federates with once (to deliver the toot). Assuming 100M followers, that'd be 100k requests with a user/instance avg. of 1k, or 10k with an user avg. of 10k. Doable.
The receiving instances know which users need to receive the toot, so that part is up to them.
@pfigel Yeah once optimized enough it's doable, but still much more expensive for that person. I'm thinking that would really made adoption harder.
@CobaltVelvet That's certainly true. OTOH, if Mastodon picks up speed and a big players (perhaps a company whose social media ventures have failed in the past *cough* Google) decides to get involved and run an instance, that might be less of a concern for celebrities.
@pfigel That's also very true.
@CobaltVelvet Receiving replies/boosts/favs on the celebrity instance will be a harder problem. They could probably only be operated by a few big entities.
I'd definitely agree that centralized solutions have an easier time here, though even Twitter had to spend a lot of time on that architecture. Still, it's not an impossible thing.