Pakes, ArielLewis, GregoryEdelman, Benjamin G.Lai, Zhenyu2015-07-172015-052015-05-112015Lai, Zhenyu. 2015. Essays in the Industrial Organization of Internet Markets. Doctoral dissertation, Harvard University, Graduate School of Arts & Sciences.http://nrs.harvard.edu/urn-3:HUL.InstRepos:17467354This dissertation contains essays that explore the incentives, mechanisms and strategies of platforms in concentrated internet markets. The first essay studies how two-sided platforms compete and set dynamic prices. In the daily deals industry, an expected increase in competition for seller participation prompted a cross-side response by the dominant platform, Groupon, to lower prices on deal coupons sold to attract platform users. I use a dynamic model of competing daily deals platforms to investigate why we observe a larger downward price response in markets where platforms have similar shares of users. Simulations show a sharp increase in value of an additional user as cross-side competition intensifies for profits from being the future platform leader. The second essay---coauthored with Benjamin G. Edelman---examines how competition is mediated by search intermediaries, looking at the design of search engines' own services and the effects on users' choices. We evaluate a natural experiment, and find that Google's prominent placement of its Flight Search service increased clicks on paid advertising listings while decreasing the clicks on organic search listings by a similar quantity. Empirical results and a controlled experiment links the mechanism to users' heterogeneous methods of search. The third essay---coauthored with Michael Egesdal and Che-Lin Su---develops empirical tools for estimating dynamic discrete-choice games. We formulate the maximum-likelihood estimator as a constrained optimization problem to be solved using state-of-the-art constrained optimization solvers. Monte Carlo results show that the constrained optimization approach has improved convergence properties over other popular computational methods.application/pdfenEconomics, GeneralEconomics, Commerce-BusinessEconomics, TheoryThesis or Dissertation2015-07-17