Notes have different kinds. Regular text notes are kind=1. DMs are kind=4. Deletions are kind=5. Reactions (🤙) are kind=7, and so on.

When you report a post, your client creates a note with kind=1984 that links to the reported post. Each really you use receives your report note. Anyone following you will get the report from those relays.

It’s up to each relay and client what they want to do with such reports.

Hey, I'm the Nostr CEO. Reports go directly to me. If i deem the report valid, I put a 0.01BTC bounty on the head of the one who posted a malicious note.