Metcalfe's Law says that the value of a network is equivalent to the square of the number of connected users of the system. In other words, as networks grow, the utility of being connected to the network not only grows, but does so exponentially. Thus when a person is added to the network, all network members are affected.
As the bandwidth available through the network continues to grow, Metcalfe's Law dictates that the value of a connection increases exponentially. The ratio of the cost of Internet access to the value it provides plummets over time. And as it plummets, connectivity and higher-bandwidth connections become that much more important, generating more usage and more capital to upgrade the network.