Large public displays are becoming a ubiquitous resource in the urban environment. Interconnected over the Internet these hitherto isolated “ad displays” could become a novel and powerful communication medium – networked public displays. One example for such a novel type of communication is their use as community tools. Scattered across the urban landscape and equipped with additional sensors, such as cameras, they provide the opportunity for local community members to take images of themselves and leave their “mark” in the setting, e.g., on their way to school, work, or meeting with friends. In order to understand the potential of posting situated snapshots on networked public displays in the context of place-based communities we designed and developed the Moment Machine – a networked public display application that allows one-click photo capture. In this paper we report on identified opportunities and challenges emerging from 6 user trials in the wild at 2 locations.