Mechanism design is a form of optimization developed in economic theory. It casts economists as institutional engineers, choosing an outcome and then arranging a set of market rules and conditions to achieve it. The toolkit from mechanism design is widely used in economics, policymaking, and now in building and managing online environments. Mechanism design has become one of the most pervasive yet inconspicuous influences on the digital mediation of social life. Its optimizing schemes structure online advertising markets and other multi-sided platform businesses. But as it drifts into new digital world, mechanism design may have morphed into something different, and the normative and practical justifications for using mechanism design to orchestrate human interactions and choices are losing traction. In this paper, Lee McGuigan, Jake Goldenfein, and Salome Viljoen argue that mechanism design, applied in algorithmic environments, has become a tool for producing information domination, distributing social costs in ways that benefit designers, and controlling and coordinating participants in multi-sided platforms.