The song title refers to the idea that everyone is on average approximately six steps away from any other person on Earth. The phrase was coined by an American academic, Stanley Milgram, after his "small world experiment" in 1967 in which he sent several packages to 160 random people living in Omaha, Nebraska, asking them to forward the packet only to others they knew by name. The aim was to get it, eventually, to a set final individual, a stockbroker from Boston, Massachusetts. The average number of times it was passed on, he said, was six. Hence, the six degrees of separation.