That’s where the concept of different Event Kinds come in. If an event kind is added to the protocol that specifies it’s a product listing, a client like Damus won’t show those unless it specifically includes that event kind in its feed
Discussion
Ahh gotcha, didn't realize different even types could be used in that way. To use a special event type in an application would it need to be "registered" in any way or do you just kinda go for it?
You'd probably need an NIP on https://github.com/nostr-protocol/nips giving details of the new event type & how it's to be handled. Atleast that's what happened for zaps & badges
^ what #[4] said