+1. In my old city, local buy/sell Telegram groups were popular. You could find anything there (products, jobs, rentals, local events). Informal, KYC-free and for cash.

I wonder if there is a group feature for Nostr (users can join a group and only group members can see the messages, maybe a relay could be configured like this?).

It would be nice to have global marketplaces, as well as private local marketplaces for villages/cities/regions (e.g. food from local farmers, taxi/delivery services, rentals, jobs, events).

Will be interesting to see what apps can be built on Nostr's relay/client/post structure.