This paper describes the different forces that shape the market structure of four different "online platform ecosystems" and the competition between them. The paper focuses on the following categories of platforms, which represent a wide scope of online activities: (i) e-commerce marketplaces;...

We present a general and tractable oligopoly model of multi-sided platforms with endogenous side and platform choices of heterogeneous end-users, considering any mix of single-homing and multi-homing platforms and in which participating on one side could preclude doing so on others. We show the...