Linkedin distance

It seems now everybody on the planet uses Linkedin. Not only IT specialists do, but normal people as well. And Linkedin has nice little feature that is if you're viewing a person's profile, and s/he is in your network (you are connected to them via somebody of your shared connections), Linkedin is showing the distance between this person and yourself. 

For one, say, you know Bob and Bob knows Alice, but you don't. Then the distance between you and Alice would be 2 hops, while Bob-you and Bob-Alice makes simply 1.

Not fun yet? Well then, substitute Alice with some celebrity and see how many persons you're away from them. I took Barack Obama and know what - it appears that the distance between mr. President and me is just 3 hops. 

Well, it's no wonder, taking into account that Obama has 500+ connections (I believe, people behind Obama's profile on the Linkedin timidly accept any invitation).

Next I picked Bjarne Stroustrup and Linus Torvalds and was kind of surprised of the same distance of 3 hops, despite both Bjarne and Linus seem picky about whom they're connected to: 128 (nice, heh) and 181 direct connections, respectively. 

Then I took Andrei Alexandrescu and Erich Gamma who appeared not connected to me. I made it to 500+ connections of Grady Booch, but missed lucky five of Bill Gates'.

Finally, I checked dozen more persons, and now am ready to postulate the rule of Linkedin distance: for any given person on Linkedin, either you're not connected to them or distance between you two is less or equal than 3.

Go check it for yourself, really.