Networks effects, some links

Dion Hinchliffe made a revision of the topic some time ago and explained that a project that want to exploit their potential need to foster it: "If you have a million people visiting your Web site but you're not leveraging network effects with them (such as by letting them contribute and letting others see and respond to those contributions), then you're probably squandering the greater part of the value of that million person audience."

There is also some links to the theories behind, Meltcalfe, Reed and Bob Briscoe, Andrew Odlyzko, and Benjamin Tilly.