This is an interesting departure from Metcalfe's Law [ the value of the network is proportionate to the square of the number of nodes in the network ].

Perhaps Metcalfe's Law applies up to a certain size, and then tails off thereafter.

There is a limit on the number of people that us humans can reasonably be expected to have friendships with. I have a feeling that it is substantially smaller than the number of 'friends' that facebook attracts.