The digitalization and personal use of media technologies have destabilized the traditional dichotomization between mass communication and interpersonal communication, and therefore between mass media and personal media (e.g. mobile phones, email, instant messenger, blogs and photo-sharing services). As private individuals use media technologies to create and share personal expressions through digital networks, previous characteristics of mass media as providers of generally accessible information are no longer accurate. This article may be situated within a medium-theoretical tradition, as it elucidates technical and social dimensions of personal media and revises the distinction between mass media and personal media. A two-dimensional model suggests locating personal media and mass media according to an interactional axis and an institutional/professional axis: personal media are de-institutionalized/de-professionalized and facilitate mediated interaction. The implementation of digital media technologies has important consequences for social networks and fits well within a theoretical discussion of the post-traditional self.