In this paper we propose an analysis of Cloud Computing as a new kind of socio-technical system. For many organizations, moving ICT from the capital expenditure line to the operational expenditure line, by using "ICT services on-demand" and paying them by consumption, is an opportunity. From another perspective Cloud Computing represents a big shift back towards centralized architectures where end-users and organizations will use on.demand resources provided by very large datacentres. Are we moving from the "autonomy" of the 1980's introduced by Personal Computing to the "heteronomy" of Cloud Computing of the XXI century? For analysing the main social and ethical issues related to Cloud Computing we propose a simple model based on the Socio-Technical Systems concept. The co-shaping between society and technology is clean-cut and can be a useful tool for users and organisations that are considering to enter into the world of ICT as-a-service. We finally investigate possible connections between our reflections about Cloud Computing and more deep ethical, philosophical, and psychological ways of addressing these issues.