'You got tagged!': the city as a playground

This paper introduces CitiTag, a collaborative project focused on social experiences and group play in public spaces, based on the awareness of other peoples' presence, through the use of mobile technology. Cititag is a wireless location based multiplayer game inspired by the concept of playground 'tag' and motivated by the hypothesis that simple rules based on presence states can result in an enjoyable and variable social experience, stimulated by real world interaction among players and group dynamics. The paper discusses the concept, design and first user study of CitiTag.