Central features of today's electronic communications markets are complementarities between the different layers of the value chain, substitutability between some applications, network effects in the provision of content and services, two-sided business models that partly involve indirect...

We introduce a flexible model of telecommunications network competition with non-uniform calling patterns, which account for the fact that customers tend to make most calls to a small set of contacts. Equilibrium call prices are distorted away from marginal cost, and competitive intensity is...