We study competitive interactions between Intel and Microsoft, two producers of complementary products. In a system of complements, like the PC, the value of the final product depends on how well the different components work together. This, in turn, depends on the firms' investment in...

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 network effects,...

"We study competitive interaction between two alternative models of digital content distribution over the Internet: peer-to-peer (p2p) file sharing and centralized client-server distribution. We present microfoundations for a stylized model of p2p file sharing where all peers are endowed with...

Katz and Shapiro (1985) study systems compatibility in settings with one-sided platforms and direct network externalities. We consider systems compatibility in settings with two-sided platforms and indirect network externalities to develop an explanation why markets with two-sided platforms are...

We analyze the optimal strategy of a high-quality incumbent that faces a low-quality ad-sponsored competitor. In addition to competing through adjustments of tactical variables such as price or advertising intensity, we allow the incumbent to consider changes in its business model. We consider...