Metcalfe's Law after [Bob Metcalfe] states that
the usefulness, or utility, of a network equals the square of the number of users.
i.e. for N users the value grows proportional to N^^2^^
This only takes into account peer-to-peer connections (e.g. telephone calls). ReedsLaw applies to networks in which group-forming takes place.
[ http://www.synesthesia.co.uk/blog/images/network.gif ]