nostr:npub19fywau9ff6pjmjek7k4kukgdcdf7w4chne57upj5s7y87gk7v27qx7n5nv 
If you dig into the technical details, it is a system that's less invasive than the current tracking models companies use with cookies and the like. The topics are calculated entirely client-side, and websites querying for them get at most 3 topics, with a 5% chance that one of the topics calculated for the week they're supplied is randomly chosen from the ~3-400 topics that are possible to be chosen.