On space, place, and personhood in post-unification Berlin. In what sense are mobile phones, and related devices, mobile? Mobile phones, and mobile computing generally, facilitate particular kinds of mobility - especially elite, cosmopolitan, voluntary forms of movement and circulation - due in no small part to their user interface design. But what counts as movement, culturally speaking? How are mobile devices mobile in relation to the body? When are they characterized instead by locatability, for example, in relation to location-based services? This talk takes up these questions to consider how circles of friends in Berlin interact with the interface design of mobile technologies, especially smartphones, which expect a singular, indivisible subject as the user. Everyday mobile phone practices often challenge implicit norms built in to mobile devices, with implications for sociality, mobility, and experiences of urban space.