This paper analyzes the optimal protection strategy for an innovator of a complex innovation who faces the risk of imitation by a competitor. We suppose that the innovation can be continuously fragmented into sub-innovations. We characterize the optimal mix of patent and trade secrets when the...

In many markets, user benefits depend on participation and usage decisions of other users giving rise to network effects. Intermediaries manage these network effects and thus act as platforms that bring users together. This paper reviews key findings from the literature on network effects and...

Competition between two-sided platforms is shaped by the possibility of multihoming. If users on both sides singlehome, each platform provides users on either side exclusive access to its users on the other side. In contrast, if users on one side can multihome, platforms exert monopoly power on...

Two types of agents interact on a pre-existing free platform. Agents value positively the presence of agents of the other type but may value negatively the presence of agents of their own type. We ask whether a new platform can find fees and subsidies so as to divert agents from the existing...

In a standard adverse selection world, asymmetric information about product quality leads to quality deterioration in the market. Suppose that a higher investment level makes the realization of high quality more likely. Then, if consumers observe the investment (but not the realization of...

This article reviews recent theoretical contributions on digital piracy. It starts by elaborating on the reasons for intellectual property protection, by reporting a few facts about copyright protection, and by examining reasons to become a digital pirate. Next, it provides an exploration of the...

We consider the effects of taxes for competing two-sided platforms. We first detail how a platform passes a tax increase on its prices. Adding price competition, we study next how the tax affects profits. Because of the strategic implications of the cross-side external effects, the tax increase...