As I said in my last event I don't know what is the Nostrs scope in your mind. But as you know we are able to bring roughly anything over Nostr.
I just find some of them that are not exist yet interesting:
1. 2FA apps: like Google authenticator. If we consider future Nostr based apps, we may lose the need of them, but currently they are widely used and keeping the secret on encrypted events over relays will be cool.
2. DOI: if you need a digital object indentifier, you need to ask a central authority to register it for you. Retarded. You can just publish an addressable event and keep your digital object data there. Then reference it with `d` tag + kind + pubkey combonation. (Kind me be ignored if someone make an standard(?) one).
3. Datasets and ML models: like hugging face that you can share these kind of stuff there, you can simply publish them in Nostr as a protocol, not a platform.
4. Version control system: we already have GIT out there, working great. But any version control system can publish its records and logs over Nostr like GIT. So we can keep track of there.
5. Journal articles and technical papers: you can publish them on Nostr without any permission and it can gain credit overtime by getting reviewed permissionlessly from different people. This one is a little more complex but I believe it's possible. Also I think we have similar or even exact stuff out there. Difference are subtle sometimes.
