One-Way Networks, Two-Way Networks, Compatibility, and Antitrust

This paper develops some important concepts with respect to networks and compatibility. We note that the familiar concept of complementarity lies at the heart of the concept of compatibility. We further note the distinction between two-way networks (e.g., telephones, railroads, the Internet) and one-way networks (e.g., ATMs, television, distribution and service networks). In the former, additional customers usually yield direct externalities to other customers; in the latter the externalities are indirect, through increases in the number of varieties (and lower prices) of components. Most industries involve vertically related components and thus are conceptually similar to one-way networks. Accordingly, our analysis of networks has broad applicability to many industrial frameworks. We proceed by exploring the implications of networks and compatibility for antitrust and regulatory policy in three areas: mergers, joint ventures, and vertical restraints.