I wasn’t quite sure what happened when I @mentioned another pinner in a pin caption, so I tested it today. When I typed the “@” symbol, followed by my other account name, Pinterest started displaying a list of possible pinners. I selected the one I wanted, and Pinterest inserted the full User Name into the pin’s description.
When I checked the email associated with the other account, I found this message:
Now you know, too. If you repin pins that have @mentions of other pinners, delete the @+name and spare them one more email.