Social efficiency of entry: Implications of network externalities

We examine the welfare effects of entry in the presence of network externalities. We show that if network goods are fully incompatible, entry is socially insufficient as long as the entry cost is high, the goods are sufficiently differentiated, and the degree of network externality is low. Further, we show that as the degree of compatibility between the network goods increases, insufficient entry becomes more likely. Our findings provide policy guidelines for anticompetitive and procompetitive entry regulations.