alt Hacker NewsIn Mastodon/AP, different instances talk to each other which creates the scale problem you’re mentioning.
AT doesn’t have this kind of issue even without Relays. This is because PDS never talks to another PDS so there’s no quadratic growth of edges. PDS only talks to apps, and there’s limited amount of apps on the network. And end users hit apps which cache stuff, so apps tend to take the user traffic hit.
Relays are helpful more on the app side because you don’t want to teach each app to crawl PDS’s and subscribe to them.
I didn’t dive into Relays in the article because they’re kind of a “next obvious optimization” but not really inherent to the model. There are other models like apps hitting shared backlink caches (like Constellation). Relay isn’t fundamental in the way hosting and apps are.
Wouldn't I have the same quadratic growth (if not worse) if each community were to self-host their app view and relay?
> because you don’t want to teach each app to crawl PDS’s and subscribe to them
Why not?
If I want true decentralization, that means no central component. For the same reason that communities and individuals host their own RSS readers, each community will in the end also have to host their own relay and app view.
The benefits of decentralisation, including fault-resistance and censorship-resistance, can only manifest once every community is self-hosting their own relay and app view.