The paper's aim is a new analysis of the origins of Arpanet, the network that linked together universities and research centres, and that later changed its name and it is now called «Internet». I want to underline the convergence between the cognitive approach by Norbert Wiener, the father of cybernetics, and the technical projects by J.C.R. Licklider and Bob Taylor, the two principal pioneers of Arpanet's birth. The thesis of the paper is that the hypothesis that the computer could be used as a communication device had its roots in the cybernetics approach to communication considered as an interactive activity. Though it is clear that the influence of cybernetics was very effective on the vision of Arpanet's pioneers, they lacked Wiener's sensibility about the risks of a potential technology misuse and their tragic consequences on society. The paper investigates also the reasons for this deep difference in the evaluation of the impact of communication technology over society, while Licklider and Taylor shared with Wiener a common vision about many characteristics of the communication facilities.