Targeted advertising can benefit consumers through lower prices for access to websites, Yet, if consumers dislike that websites collect their personal information, their welfare may go down. We study competition for consumers between websites that can show targeted advertisements. We find that...

We study a platform's design of membership and transaction fees when sellers compete and buyers cannot observe the prices and features of goods without incurring search costs. The platform alleviates sellers' competition by charging them transaction fees that increase with sales revenue, and...

Many online businesses, including most of the largest platforms, seek and provide attention. These online attention rivals provide products and features to obtain the attention of consumers and sell some of that attention, through other products and services, to merchants, developers and others...

Should the FTC have allowed Zillow to acquire its foremost rival, Trulia? It is increasingly well-accepted that digital platforms tend toward dominance in their immediately adjacent relevant-product markets. Google, for example, has long held a majority share of the markets for general-search...

This online appendix to "Insulated Platform Competition" includes proofs and details of our applications.The paper to which these Appendices apply is available at the following URL: "http://ssrn.com/abstract=1694317" http://ssrn.com/abstract=1694317

Recent claims that online platforms have secured permanent monopolies, protected by barriers to entry from network effects and stockpiles of data, and should be the focus of intense antitrust and regulatory scrutiny, are inconsistent with the economics, technology, and history of online...

Digital platforms frequently refer their users to competitors. We show that these references induce a business-sharing effect that may relax competition for users, resulting in lower quality of content. More surprisingly, user surplus may also decrease as the quality effect may overwhelm the...