Web 2.0 tools, including blogs, wikis, and photo sharing and social networking sites, have made possible a more participatory Internet experience. Much of this technology is available for mobile phones, where it can be integrated with such device-specific features as sensors and GPS. From Social Butterfly to Engaged Citizen examines how this increasingly open, collaborative, and personalizable technology is shaping not just our social interactions but new kinds of civic engagement with cities, communities, and spaces. It offers analyses and studies from around the world that explore how the power of social technologies can be harnessed for social engagement in urban areas. Chapters by leading researchers in the emerging field of urban informatics outline the theoretical context of their inquiries, describing a new view of the city as a hybrid that merges digital and physical worlds; examine technology-aided engagement involving issues of food, the environment, and sustainability; explore the creative use of location-based mobile technology in cities from Melbourne, Australia, to Dhaka, Bangladesh; study technological innovations for improving civic engagement; and discuss design research approaches for understanding the development of sentient real-time cities, including interaction portals and robots.