The author thanks Natalia Fabra and Matilde Pinto Machado for their patient guidance and advice. The author also thanks Victor Aguirregabiria, Heski Bar-Isaac, Marc Bourreau, David P. Byrne, Jesús Carro, Ambarish Chandra, Alan Crawford, Alexandre de Cornière, Rahul Deb, Daniel Ershov, Chiara Farronato, Alberto Galasso, Dominik Gutt, Ignatius J. Horstmann, Belén Jerez, Bruno Jullien, Gerard Llobet, Leonardo Madio, Luigi Minale, Matthew Mitchell, Maryam Saeedi, Jan Stuhler, Mark Tremblay, and Gabor Virag. Helpful feedback was received at the internal seminars at Universidad Carlos III de Madrid, Center for Monetary and Financial Studies, and Rotman School of Management and at the Doctoral Workshop on The Economics of Digitization, the 2019 Center for Economic and Policy Research / Journal of Industrial Economics School on Applied Industrial Organisation, and the Toulouse School of Economics Digital Workshop. All errors are mine.