Mass gatherings and the positive or negative phantasms of the masses instigate various discourses and practices of social control, communication, and community formation. Yet the masses are not what they once were. In light of the algorithmic analysis of mass data, the diagnosis of dispersed public spheres in the age of digital media, and new conceptions of the masses such as swarms, flash mobs, and multitudes, the emergence, functions, and effects of today’s digital masses need to be examined and discussed anew. They provide us, moreover, with an opportunity to reevaluate the cultural and medial historiography of the masses. The present volume outlines the contours of this new field of research and brings together a collection of studies that analyze the differences between the new and former masses, their distinct media-technical conditions, and the political consequences of current mass phenomena.