Some mysterious dude that works with you, that keeps spamming your mailbox and that you probably have hung out with a couple of times.
But that you unfortunately STILL dont know who is because in the real world he is just a face and in your mailbox he is just a name with no connection between the two whatsoever.
"Who the fuck is that Thorben over there?"
"Are you serious? You have been chatting with him all day on the company message system!"