Because relays, from my understanding and experience, aren't built to propagate (discover other relays, store relay addresses, share them with other relays, store and push specific data/events). My relay list is in r1, r2, r3 Someone has my npub in their follow list, and they're looking at relays r4, r5, r6 (and the relays in my relay list aren't the same as that someone) They won't see my posts. --- DNN nodes propogate data with each other (only specific events, one of which would include relays an npub posts to). So assuming I have acquired a DNN ID (meaning my npub is in DNN nodes where they'd fetch and propogate data/events), then when someone follows me/npub, the client would fetch the data from a dnn node of where I'd post to and check those relays > they'd see my posts.