The number of acquaintances who stand between any two people on Facebook? It’s 4.74, according to a new study by researchers at Facebook and the University of Milan.

The study updates the popular “Six Degrees of Separation” theory first espoused by psychologist Stanley Milgram in 1967 and later popularized by the parlor game, “Six Degrees of Kevin Bacon,” in which seemingly unconnected celebrities are shown to have a relationship to the Hollywood star.

The Facebook study used a set of algorithms developed by researchers at the University of Milan to calculate the average degree of separation between any two people. The study found that the average number of “hops” from one person to another was 4.74 degrees. In the United States, where more than half of people over the age of 13 are Facebook users, the degree of separation was even smaller – 4.37.

The Facebook study reminds us that the world is increasingly becoming a “Global Village,” a concept the philosopher and scholar Marshall McLuhan popularized in the 1960s when he described how the vast globe has become transformed into a small village by virtue of technology. McLuhan was thinking about television, but he might just as well have been describing the Internet.

The study also begs the question of just who, exactly is a friend. A person could have several hundred Facebook friends and yet have little real contact with any of them. As Jon Kleinberg, a computer science professor at Cornell and a faculty advisor to an author of the Facebook study, told the New York Times: “We are close, in a sense, to people who don’t necessarily like us, sympathize with us or have anything in common with us. It’s the weak ties that make the world small.”

Indeed.