Compatibility Under Differentiated Duopoly with Network Externalities

Abstract

This paper investigates a firm’s equilibrium behavior under product compatibility, product differentiation, and the network effect. We find that a firm with a higher degree of compatibility has a greater competitive disadvantage due to its higher spillover effect with other firms. A firm under Cournot competition can increase its demand and profit by decreasing consumers’ subjective belief about the degree of differentiation between products, when the firm’s product compatibility and/or relative production cost is sufficiently small. When the relative production cost satisfies certain conditions, the principle of maximum differentiation exists. However, the principle of minimum differentiation never exists. Furthermore, when firms can freely determine their own compatibility, each firm will choose the lowest degree of compatibility, in contrast to the social optimum in which both firms choose the highest degree of compatibility. A social dilemma occurs.