Markets for Information: An Introduction

We survey a recent and growing literature on markets for information. We offer a comprehensive view of information markets through an integrated model of consumers, information intermediaries, and rms. The model embeds a large set of applications ranging from sponsored search advertising to credit scores to information sharing among competitors. We then review a mechanism design approach to selling information in greater detail. We distinguish between ex ante sales of information (the buyer acquires an information structure) and ex post sales (the buyer pays for speci c realizations). We relate this distinction to the different products that brokers, advertisers, and publishers use to trade consumer information online. We discuss the endogenous limits to the trade of information that derive from its potential adverse use for consumers. Finally we revisit the role of recommender systems and arti cial intelligence systems as markets for indirect information.