This dissertation is a collection of three essays on the topic of strategic mediation of information. A recurring theme is a presence of the information intermediary influencing the interaction between informed and uninformed parties.

Chapter 1 studies communication between an informed sender and an uninformed receiver with a presence of a strategic fact-checker. I show that if the cost of checking is small, the optimal fact-checking policy is full fact-checking; otherwise, no fact-checking is optimal. The receiver need not prefer a fact-checker with preferences aligned with the receiver to one with opposed preferences. Adding multiple fact-checkers does not necessarily improve communication even when all fact-checkers are willing to fully check by themselves.

Chapter 2 considers an online platform that intermediates trade between sellers and buyers using data records of the buyers' personal characteristics. An important component of the value of a data record for the platform is a novel externality that arises when a platform pools records to withhold information from the sellers. Ignoring this externality can significantly bias our understanding of the value of data records. Chapter 2 then characterizes a platform's willingness to pay for more data, thereby establishing a series of basic properties of the demand side of data markets.

Chapter 3 presents the optimal editorial policy for state-owned media manipulating information flow from a strategic informed elite to an uninformed receiver. I show conditions on players' preferences under which media meaningfully communicate information on the ruler's competence. An elite that is more aligned with the media benefits the media, as long as the alignment is not too close. The media are worse off when the receiver is more critical of the ruler, whereas the elite generally is better off when the receiver is more critical. I characterize the lower bound on the media’s payoff when the receiver has private information about how critical he is.