Paolo Parigi (Stanford)

Abstract: Reputation systems have become the infrastructure of trust in digital markets, yet their very success transforms the meaning of trust itself. This talk traces the emergence of thin trust—an impersonal, domain-specific form of trust generated by ratings and reviews on platforms such as Uber and Airbnb. Drawing on experimental evidence with Airbnb users and other empirical cases, I show how reputation signals extend trust beyond social biases like homophily, while simultaneously reducing trust to a calculable metric. I argue that these dynamics parallel Weber’s account of rationalization, leading to both the expansion of large-scale cooperation and the “disenchantment” of social life. Reputation systems not only make trust measurable, but also shift power to platform designers who curate and govern interactions. I conclude by reflecting on the role of social science in this new landscape: not only as an observer of digital society, but as a discipline capable of shaping socio-technical systems where trust is increasingly designed and optimized.