Hodlbod's book reffers to this as the routing problem. Great read if anyone wants to understand the different ways clients can read data from relays
the nostr relay model is a double-edged sword, especially if your client needs to aggregate data from a bunch of pubkeys: dump pipes makes writing and running relays a breeze but dumps all the complexity to clients. now you don't need a backend but you do have to implement caching, storage and indexing on the client side with subpar primitives (at least on the web) just to get a half decent UX. i'm convinced that clients centered around relays are the sanest way to build apps: nostr:npub17n4cuc4d6y6qh89dekvxrenfkt5s0n49xns00uavjaxpr36c55dq87fyh9 and nostr:npub1gm7gw8q6akeft2pjt270we35vlff0v9g2fene6cxkz2h68q5hl6qls0fte embrace this idea.
Discussion
it's on my to-read list. the routing problem is nostr's biggest issue for building reliable clients imo.