Three and a half degrees of separation - Facebook Research
In honor of Friends Day, we've recalculated the classic 'Six degrees of separation' statistic for everyone who uses Facebook and determined that the number is actually 3.57. Each person in the world (at least among the 1.55 billion people active on Facebook) is connected to every other person by an average of three and a half steps.
4 Feb 2016 ... Playwrights [1], poets [2], and scientists [3] have proposed that everyone on the planet is connected to everyone else by six other people.