Book excerpt: The developments in digital television technology provide the unprecedented opportunity to drastically extend the role of television as a content delivery channel. E-health, e-commerce, e-government, and e-learning are only a few examples of value-added services provided over digital televisions infrastructures. These changes in the television industry challenge companies to adjust their strategies in order to meet the opportunities and threats in this new environment. Interactive Digital Television: Techniques and Applications presents the developments in the domain of interactive digital television covering both technical and business aspects. This book focuses on analyzing concepts, research issues, and methodological approaches, presenting existing solutions such as systems and prototypes for researchers, academicians, scholars, professionals and practitioners.