Here’s our simplified way of looking at it:
In the beginning, RSS was used to distribute and aggregate content from different websites. Content creators usually had their own independent sites to publish content, while readers typically didn’t have websites of their own for publishing.
Then Twitter came along — all registered users could post content directly to Twitter’s servers, and its built‑in follow system effectively replaced RSS.
With Nostr, users publish content to different relays, and its follow mechanism works more like RSS.