i don't think that's true as most people are in stuff like loops where people are usually connected to others the same people their friends are connected to ex. all my classmates are friends to eachother or the whole family are friends
this makes this review look strange
the minimum number of steps (if everyone had a different friend than the previous one or other branched friends) = log(avg. no. of friends, total facebook users) = log (190, 800000000) = 3.907 i think loops cancel most of that so it could reach 15-20 steps or so (maybe infinite for some people/groups)
BTW i never used facebook and i'll never use it