The authors thank Santiago Balseiro, Bryan Bollinger, Mingyu (Max) Joo, Giuseppe Lopomo, Kenneth Wilbur, Hema Yoganarasimhan, Song Yao, and seminar participants at the 2019 Conference on Digital Experimentation, 2020 Frank M. Bass Frontiers of Research in Marketing Science Conference, Arizona State University Statistics, Boston College, Boston University, Carnegie Mellon University, City University of Hong Kong, the University College London, the University of Colorado Boulder, Cornell University, Duke-University of North Carolina at Chapel Hill Brownbag, Facebook Econ/Algorithms Meeting, the University of Georgia, Harvard University, HEC Paris, the Hong Kong University of Science and Technology, the University of Illinois at Urbana-Champaign, Johns Hopkins University, Junior Faculty Development Forum at Washington University in St. Louis, Lingnan University, the University of Miami, Marketing Science Institute State of Marketing Science Summit, Northwestern University, the University of Notre Dame, the University of Toronto, Rice University, the University of Rochester, Southern Methodist University, Stanford University, the University of Texas at Austin, Tilburg University, U.S. Department of Justice, the University of Vienna, and Yonsei University for comments and suggestions. The data provider has a right to review the manuscript for the following conditions: the name of the data provider or its affiliates is not used; no data or any information from which the identity of the data provider or its affiliates could be inferred is used; no information relating to visitation frequencies, traffic levels or sales levels on the data provider affiliates’ sites is disclosed, except for anonymous references to small portions or samples of the data provider affiliates, and from which overall traffic and sales patterns of the data provider affiliates’ sites cannot be determined; and no personal data are presented that identifies registrants or users of the data provider sites.