On the island where we have our summer house, everyone introduces themselves to new people with the house number: “Hi, my name is this´n´that, house 42”. That´s funny, it´s as if that number is part of one´s identity there. I´d never introduce myself that way at home, with my name and address. The house number is almost like a membership id, and if someone else too introduces himself with a house number, you know that oh, he´s one of us. No further explanations needed. Sort of like a secret hand shake.