The aim of the thesis is to describe selected consequences of informatization on the basis of three different views' critical synthesis. First view is an historical perspective focused on medialisation of information and its influence on shaping of man's thinking. On the background of technological progress are shown the milestones in changing of social reality. Another view is to describe the infromation society as a present phenomenon with its general characteristics. The last point of view is based on the hypothesis sof Global brain, which describes mankind as a network of nerve cells, connected to global computer network. Thesis is not intended to be a comprehesive overview of the informatization's consequences but it tries to explain basic issues related to information society.