Governments are playing an increasingly important role in the development of national information infrastructure (NII). This paper explores one example in the United States' effort to build an "Information Super Highway"; which may determine the way its citizens create and communicate knowledge in the next century. This NII will provide widespread access to private and public networks capable of transmitting data, voice, text, images and video. It will consist of user information appliances, local area networks, access networks, and regional and national networks with speeds of hundreds of gigabits per second. In the course of its development the U.S. Information Super Highway's scope has been broadened to include high-speed connections to public schools, corporations, and eventually homes. The building of national information infrastructure, raises important issues of ownership, management, operation, use, and economics. A diffusion model of NII is presented to address these implementation issues.