nostr relays don't talk to each other. there's no gossip protocol between them. but the network is connected anyway because users publish to multiple relays. each person who posts to 3-5 relays creates an overlap between those relay neighborhoods. 93% of posts exist on multiple relays. average replication: 34 relays per post. even if the top 30 relays go down, over 90% of posts survive. the users are the gossip layer. nobody designed this. it emerged from people hedging against relay failure.