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peb
02-06-2016, 10:57 AM
http://mobile.nytimes.com/2016/02/05/technology/six-degrees-of-separation-facebook-finds-a-smaller-number.html?referer=https://www.bing.com/search?q=facebook%20degrees%20of%20separation&form=MB1078&mkt=en-US&setlang=en-US





I think 4 is probably a little low. I have always bought into the traditional number of 6. Probably 5 for a lot of people.

It's easy to get to almost any country in 2 or 3. From there, one should be able to get to a city in 1 or 2 more. Then reach the destination I 1 or 2 more. So I am sure there are people in the world it could take 7 steps to reach, but not many.



Of course facebook does not have to follow a geographical search algorithm.

peb
02-06-2016, 11:08 AM
For those of you with a computer science background, do you know if the problem of finding the most distant vertex in a graph reduces to the travelling salesman problem? if so, facebook has spent some serious CPU cycles determining this.

It must not.

xflow7
02-06-2016, 11:15 AM
One thing about their observation that the number is quite a bit lower than 6 is that Facebook's definition of "acquaintance" is likely quite a bit more generous than the definition in effect when the original value of 6 was claimed. If they're going by Facebook "friends" they are likely including many connections between people who have never actually met. There are surely cases where two people who don't know each other directly "friend" each other after exchanging comments on the same FB feed and finding they have stuff in common. That now reduces the distance between them and their networks by at least one, even though they'd never have been considered acquaintances by any pre-2005 definition.

Dave