The mobile phone has become the central node of the ensemble of portable objects that urbanites carry with them as they negotiate their way through information-rich global cities. This paper reports on a study conducted in Tokyo, Los Angeles, and London where we tracked young professionals’ use of the portable objects. By examining devices such as music players, credit cards, transit cards, keys, and ID cards in addition to mobile phones, this study seeks to understand how portable devices construct and support an individual’s institutions.

Our focus in this paper is not on the relational communication that has been the focus of most mobile communication studies, but rather on how portable devices mediate relationships to urban space and infrastructures. We identify three genres of presence in urban space that involve the combination of portable media devices, people, infrastructures, and locations: cocooning, camping, and footprinting. These place-making processes provide hints to how portable devices have reshaped the experience of space and time in global cities.