basic idea: users express interests in certain topics. when you create a topical post it only posts to people who are interested in that topic among your followers.

This will allow you to talk about niche interests without annoying people who follow you and are not interested in that topic.

nostr:note1cpa99hz7ntuupnfkhsgywa3rxtefz4texjwtwtap54pwq5ftvnzqk7w8hz