Interesting article in NYTimes about most recent replication of Milgram's famous "small world experiment". The original research introduced concept "six degrees of separation" - that any two people in the world are separated by only six intermediate connections. According to Facebook scientists, who analyzed data on 721 million active Facebook users with total of 69 billion friendships, that number now is down to 4.74. Of course, I would question definition of "friendship" used in the study (it was defined simply as a being "friends" on Facebook), nevertheless, the methodology and analysis are interesting.
More detailed report is available on Facebook Data page here.
