Page "Network effect" Paragraph 8

According to Metcalfe, the rationale behind the sale of networking cards was that ( 1 ) the cost of the network was directly proportional to the number of cards installed, but ( 2 ) the value of the network was proportional to the square of the number of users.

This was expressed algebraically as having a cost of N, and a value of N².

While the actual numbers behind this definition were never firm, the concept allowed customers to share access to expensive resources like disk drives and printers, send e-mail, and access the Internet.