Ubiquitous computing (or ubicomp) is the label for a "third wave" of computing technologies. Following the eras of the mainframe computer and the desktop PC, ubicomp is characterized by small and powerful computing devices that are worn, carried, or embedded in the world around us. The ubicomp research agenda originated at Xerox PARC in the late 1980s; these days, some form of that vision is a reality for the millions of users of Internet-enabled phones, GPS devices, wireless networks, and "smart" domestic appliances. In Divining a Digital Future, computer scientist Paul Dourish and...