A study was performed to investigate a domain for a mobile and social service, where a web of social trails is overlaid over a physical space. Using a method inspired by work of the city planner Kevin Lynch, 20 subjects were interviewed about their experiences, activities, movements and habits related to a specific shopping mall. Design implications for the service were drawn from subjects’ sketches of the area, lists of places important to them, and their daily routes through the mall as drawn on a standardized map. Three user groups were identified based on the amount of activities and time spent in the mall: dwellers, shoppers and exploiters. User sketches indicated that traditional maps are not an optimal means for visualising the mall in the service. Finally, the way subjects grouped, labelled and defined places and objects in the mall provided valuable input to the design of the service interface.