A good question! 👏🏻👏🏻👏🏻 

 No. 

Because i can spin up 20 new private keys and thats 20 new users but in reality its just me  

 you would get 20 welcome notes then  

 I don’t know of a direct way. But you can check who’s writing notes in introductions. And also on nostr.band when you search for an npub, it tells you when the npub was created 

 #introduction might be a good way 

 Could be a good start. But the npub wasnt necessarily created today