Urban screens are becoming a common element of our city landscape. As such they offer new ways of connecting people that occupy public space, e.g., by taking situated snapshots through a display-attached camera. In this paper we present a first longitudinal case study of 12 weeks of such an application -- Moment Machine -- deployed "in the wild" on an urban screen facing the street. We report findings from 1189 photos taken, 13 interviews, and 3 weeks of observations that show engagement stimulated by situated snapshots within a place-based community where the screen is located. We also analyze interaction log files to describe how often users interacted, what type of interactions they had and how long they lasted, and overall engagement on a weekly basis and throughout the week. Based on our experience, we provide three take-away snippets for designers of similar urban screen experiences.