This difference will be critical as network investors and managers plan better for growth. In North America alone, telecommunications carriers are expected to invest $65 billion this year in expanding their networks, according to the analytical firm Infonetics Research Inc., in San Jose, Calif. As we will show, our rule of thumb for estimating value also has implications for companies in the important business of managing interconnections between major networks.
The increasing value of a network as its size increases certainly lies somewhere between linear and exponential growth [see diagram, " "]. The value of a broadcast network is believed to grow linearly; it's a relationship called Sarnoff's Law, named for the pioneering RCA television executive and entrepreneur David Sarnoff. At the other extreme, exponential--that is, 2n--growth, has been called Reed's Law, in honor of computer networking and software pioneer David P. Reed. Reed proposed that the value of networks that allow the formation of groups, such as AOL's chat rooms or Yahoo's mailing lists, grows proportionally with 2n.
We admit that our n log( n ) valuation of a communications network oversimplifies the complicated question of what creates value in a network; in particular, it doesn't quantify the factors that subtract from the value of a growing network, such as an increase in spam e-mail. Our valuation cannot be proved, in the sense of a deductive argument from first principles. But if we search for a cogent description of a network's value, then n log( n ) appears to be the best choice. Not only is it supported by several quantitative arguments, but it fits in with observed developments in the economy. The n log( n ) valuation for a network provides a rough-and-ready description of the dynamics that led to the disappointingly slow growth in the value of dotâ''com companies. On the other hand, because this growth is faster than the linear growth of Sarnoff's Law, it helps explain the occasional dot-com successes we have seen.