The problem of the differentiation of societies is at the core of the sociological imagination about the rise of modernity. In postwar sociology, T. Parsons developed the theory of generalized symbolic media in the mid-1960s to tackle, theoretically and historically, the issue of differentiation. According to him, the interchange media are defined as resources oriented to exchange processes between the subsystems of the social system. Starting with money, Parsons argues that the remaining media (power, influence, and value-commitments) have a set of characteristics defined as common properties for all media. After this first formulation, contemporary theorists such as Niklas Luhmann and Jürgen Habermas have developed and modified the Parsonian theory: Luhmann rejects the idea of interchange and proposes the use of communication; Habermas distinguishes between steering and communication media. In all three cases, the focus of the theory is on the characterization of the strongest dynamics of social co-ordination present in differentiated societies. A major result of these developments is the inclusion of new dimensions on which to conceive the properties of media, not only those of money but also language. Beyond differences, then, it is proposed that there is only one theory of generalized symbolic media which can be understood as a progressive research programme, in Lakatos’ terms. Finally, the hand-in-hand evolution between the theory of media and Habermas’ and Luhmann's re-conceptualizations on societal differentiation in contemporary societies will also be revealed.