In the paper the main accent is put on the contemporary social change in the global context and its main factors that are knowledge, information and technology. The development of communication and information technologies during the last fifty years significantly inspired social thinkers to analyse thoroughly the role of the mentioned phenomena. Their reflections and conclusions resulted not only in various sociological and economic theories of social change. Such thinkers as Daniel Bell and Manuel Castells were selected for the paper partly because they coined the name for the current stage of social development, that is post-industrial society based on the changes in knowledge and information use in services in the Bell’s concept and Castells’s network society based on information production and network technologies roles in the globalized societies in the developed and developing countries all over the world. These concepts were compared with several other definitions and theories of information and knowledge in connection with communication technology development.