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News: Six-ish Degrees of Separation

Is the world getting smaller? Definitely—at least online

The idea of six degrees of separation has been around for a while...but is it true? In the late 1960s, the famous psychologist Stanley Milgram set up two experiments to see how someone in the Midwest could transmit a document to a random person in the Boston area. The senders were told only the recipients' names and selected details and were instructed to mail the package to an acquaintance they thought would be more likely to know the target. It took between two and ten connections—not including the many packages that never made it.

The digital age has brought new attempts to calculate our closeness. Today, these experiments can include many more participants, but draw only from the limited pool of people who are online. While no one has come to a conclusive answer about how far apart we all are, research suggests that—online at least—we're all getting closer. Here's a look at some recent projects that aimed to test the accuracy of the magic number six

2001

Duncan Watts, author of the book Six Degrees , re-created the Milgram experiment with an email message. More than 60,000 senders were tasked with reaching 18 targets. The average number of connections needed? Approximately six.

2008

Two researchers tracked a month of Microsoft Messenger IMs and determined that there were an average of 6.6 intermediaries between any two Messenger users.

2010

A social analytics company analyzed 5 billion Twitter connections and found that any Twitter user is 4.67 steps away from any other Twitter user—though it's worth noting that the population of Twitter users is relatively small, and users may follow people they don't actually know.

2011

Scientists at Facebook and the University of Milan studied 721 million accounts—more than a tenth of the world population. The average distance between any two users was 4.74 degrees.

2013

Using a different algorithm from the Italian study above, Taiwanese researchers analyzed the connections between nearly a billion Facebook profiles, filtering out celebrities with large networks but deliberately including people with obscure professions. The users they studied were between 18 and 48 years old, and all were speakers of one of the ten most spoken languages. The results? The average number of steps between two people was 3.9 . Kevin Bacon may be closer than you think.