Expert Critics, Rankings, and Review Aggregators: The Changing Nature of Intermediation and the Rise of Markets with Multiple Intermediaries

In this review, we integrate insights from the extensive but fragmented literature on information intermediaries. Tracing the evolution of this research, we observe a shift from a world dominated by expert critics to one where these traditional intermediaries sit alongside newer forms, such as media rankings and ratings, as well as online review aggregators. As a result of this proliferation, producers are often subject to simultaneous public evaluation by multiple intermediaries. To understand the potential impact of these changes, we build a framework that specifies the central characteristics of intermediaries and their evaluations and use this framework to compare and contrast three ideal types of intermediaries. This structured comparison reveals important differ-ences in the nature of intermediation by distinct types of intermediaries. We discuss implications for key producer outcomes and highlight important new questions for future research.