type="main" <p>We present a theory for why it might be rational for a platform to limit the number of applications available on it. Our model is based on the observation that even if users prefer application variety, applications often also exhibit direct network effects. When there are direct...</p>

We test empirically for network effects and preannouncement effects in the DVD market. We do this by measuring the effect of potential (incompatible) competition on a network undergoing growth. We find that there are network effects. The data are generally consistent with the hypothesis that the...

We address the possibility of foreclosure in markets where the final good consists of a system composed of a hardware good and complementary software and the value of the system depends on the availability of software. Foreclosure occurs when a hardware firm merges with a software firm and the...