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How small is the digital world?

Kathryn McConnachie
By Kathryn McConnachie, Digital Media Editor at ITWeb.
Johannesburg, 05 Sept 2011

Yahoo and Facebook have teamed up to revisit the longstanding theory of six degrees of separation, with the “Small World Experiment”.

“The Small World Experiment is designed to test the hypothesis that anyone in the world can get a message to anyone else in just 'six degrees of separation' by passing it from friend to friend,” says Yahoo Research.

“Sociologists have tried to prove (or disprove) this claim for decades, but it is still unresolved.”

The hypothesis was first famously tested in 1967 by sociologist Stanley Milgram. Milgram sent about 300 letters to randomly selected individuals in Omaha, Nebraska, with the only instruction to get their letter to a 'target' individual (a stockbroker in Boston).

They were given basic information about the target, including his name, occupation and address. The senders then sent the letter on to someone who they thought might be closer to the target than they were.

Milgram found the average number of steps in a chain that reached the target was six. The majority of chains did, however, not reach the target - prompting speculation that most people in the world actually can't reach each other.

The Small World Experiment by Yahoo and Facebook uses the same basic method, but all sending and receiving is done via Facebook.

Not the first

Milgram's experiment has been revisited many times, with one such example being the 2008 study by Jure Leskovec and Eric Horvitz, which analysed Windows Instant Messenger data to see what the average degree of separation on the communication network was.

“We found that the average shortest path length in the Messenger network is 6.6 (median 6), which is half a link more than the path length measured in the classic study,” says the study report.

Longer paths of up to 29 were also found though. A similar experiment was also conducted by a British journalist, Joanna Geary, earlier this year, showing how easily accessible information about strangers is online.

Geary began with a Twitter update picked at random from a search of four keywords. From that tweet alone, Geary was able to find that user's family on Facebook in just nine steps - by using different platforms such as Google, Facebook and LinkedIn.

"It frightens me how simple it was to get all that I did. I've gone from one tweet to knowing an entire family's names, location, address, contact details, what they look like, how they are connected to the military, and potentially, where a part of the US army is coming under fire,” said Geary.

“I stop there because I am already completely freaked out by just how far I've already got from a few Google searches."

Facebook familiarity

In the Small World Experiment, Yahoo Research is hoping to leverage Facebook's social graph in order to discover the current degree of separation in the digital world.

“Because Facebook allows us to know not only the friends that people choose to send their messages to, but also the entire social graph of the 750 million-plus Facebook users, we can now test the hypothesis rigorously; and that is what we intend to do,” says Yahoo Research.

The experiment was launched in August, and is still open to new participants. People can join the experiment as either a 'sender' or a 'target', by signing up on the Small World Experiment Web site. Senders will be able to track the progress of their message from the same site.

“By participating in this experiment, you'll not only get to see how you're connected to people you might never otherwise encounter, you will also be helping to advance the science of social networks,” says Yahoo Research.

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