The comment about relay being an optimization was somewhat nitpicky, you’re just using the wrong term (technically the relay is a proxy between all the PDs’ and the app view, the app view stores all the posts too and you could drop the relay and replace it with the app view(s) connecting to all the PDSs directly).

The “App View” is a server that returns the posts to display in the feed to clients (eg the mobile app). In practice the App View is what *has* to have a full copy of all the tweets, much like a nostr relay works in practice today.

Clients simply making the same request to multiple App Views wouldn’t result in having to rewrite or throw anything away, I have no idea why you’re suggesting that - in general you’ll get the same response from each, just have to merge them on the client side.