The popularity of augmented reality (AR) applications on mobile devices is increasing, but there is as yet little research on their use in real-settings. We review data from two pioneering field trials where MapLens, a magic lens that augments paper-based city maps, was used in small-group collaborative tasks. The first study compared MapLens to a digital version akin to Google Maps, the second looked at using one shared mobile device vs. using multiple devices. The studies find place-making and use of artefacts to communicate and establish common ground as predominant modes of interaction in AR-mediated collaboration with users working on tasks together despite not needing to.

Most large public displays have been used for providing information to passers-by with the primary purpose of acting as one-way information channels to individual users. We have developed a large public display to which users can send their own media content using mobile devices. The display supports multi-touch interaction, thus enabling collaborative use of the display. This display called CityWall was set up in a city center with the goal of showing information of events happening in the city. We observed two user groups who used mobile phones with upload capability during two large-scale events happening in the city. Our findings are that this kind of combined use of personal mobile devices and a large public display as a publishing forum, used collaboratively with other users, creates a unique setting that extends the group's feeling of participation in the events. We substantiate this claim with examples from user data.

We present data from detailed observations of CityWall, a large multi-touch display installed in a central location in Helsinki, Finland. During eight days of installation, 1199 persons interacted with the system in various social configurations. Videos of these encounters were examined qualitatively as well as quantitatively based on human coding of events. The data convey phenomena that arise uniquely in public use: crowding, massively parallel interaction, teamwork, games, negotiations of transitions and handovers, conflict management, gestures and overt remarks to co-present people, and "marking" the display for others. We analyze how public availability is achieved through social learning and negotiation, why interaction becomes performative and, finally, how the display restructures the public space. The multi-touch feature, gesturebased interaction, and the physical display size contributed differentially to these uses. Our findings on the social organization of the use of public displays can be useful for designing such systems for urban environments.