Are you talking about an npub or something else?
Discussion
Yes, I'm referring the @ address. People have them listed in their bio, and there are several domains that offer the 'service' of setting up the NIP-05 identity... but now it seems useless.
I think it was a useful feature back when Nostr was new and you couldn't know for sure the npub was who they claimed to be. It does seem less important now days. Either way its a useful feature if you need it.