The proper design of digital platforms as well as of the mechanisms through which platforms compete between them is crucial to avoid waste and enhance social welfare. The research work by Francesco Decarolis is advancing the frontier of our understanding of the working of digital markets. It is motivated by the consideration that the lack of a comprehensive empirical assessment of the crucial phenomena in this area driven by the lack of data availability has been the major impediment to the research in this area. His projects in this area touch on the major issues of competition digital ad data and privacy and range from the role of preset defaults and behavioral biases, to the design of the auction systems and the role of AI-assisted bidding these auctions, to self preferencing, antitrust and public interventions in the digital markets.