In this paper, we suggest utilizing modern social networking services for building versatile applications for interactive public displays. We demonstrate the functionality and potential of this approach by presenting a set of services deployed on top of a network of public displays, utilized in a longitudinal study in an authentic city setting. We further propose utilizing users' personal online profiles for building personalized and appealing public social services, and suggest that this may enhance the attractiveness of interactive public displays. Results of this study indicate that using interactive public displays is inherently a social event, and that services supporting group use and sociality succeed in urban smart spaces.