Author: Danaë Metaxa (University of Pennsylvania) 

This white paper examines the digital advertising ecosystem, with a particular focus on social inequality. It begins in Section 1 by introducing the concept of a sociotechnical system and the challenges of studying such systems empirically: these systems are dynamic, their data are ephemeral, they are embedded deeply in people’s everyday lives, and they are highly personalized. Next, Section 2 introduces the reader to digital advertising, beginning with a brief history of advertising before the digital era and continuing to explain the technical infrastructure that underlies this ecosystem. Section 3 then delves into bias and discrimination in digital ads on both a theoretical level (legal context and types of bias) and a summarization of work that has empirically studied discrimination in digital ads. Finally, Section 4 concludes by discussing why these issues persist and how we might change them—from better research to law and policy.