The aim of this research is to understand and compare the implications of recent technical changes for the development and performance of three key component sub-sectors of the primary information sector (PIS): the Information and Communication Technology supply industries; Telecommunications services and Media services. In this study, the author first reviews the most important economic theories explaining the links between technical change or progress and economic performance (i.e. Neoclassical and Neo- Schumpeterian / Evolutionary), as well as the relatively recent “New Economy” writings about the latest wave of technological innovations. Secondly, the author adopts an historical and evolutionary approach to examine the evolution of three main groups of activities representing the PIS industries in the case of the USA. The study provides an account of the main technical innovations but also the regulatory, organisational, managerial and stylistic changes that follow and complete these innovations. These changes contribute to the creation of new industries and markets and, in a fundamental way to the harvesting of their benefits. Three key groups of activities are taken as case studies for empirical and historical analyses: first, the computer industry, second, the wireline telecommunication industry, and third, the audiovisual content and distribution media services. In the case of the computer and media content industries, while providing an account of the links between innovations and economic performance, the study also examines the evolution from manufacturing-type activities into activities better described as services. In the case of the wireline telecommunication industries, the author highlights the separation of different activities into different modules and highlights the role of the regulator as current “system integrator”. The perspective adopted in this research is critical of those approaches that rely on mainstream economics to provide the main framework for explaining the effect of technical change on the economic performance of these sectors. This study, rather, emphasises the necessity of using a variety of theories to explain the evolution of these sectors. In addition to an historical and evolutionary approach, this study proposes a re-defined version of Baumol’s theory of cost disease (based on a notion of “creative inputs”). It also draws on relevant aspects of the service economics literature and modularity theories (defined as a subset of theories within the Complex Evolving Systems’ school of thought).