Cloud computing represents a new business paradigm whereby a series of computing resources are offered as a service, available on-demand, on a pay-per-use basis, over the Internet. In this paper, we propose a hypothesis of how cloud computing can be described as a complex system and we describe the various risks and opportunities connected with the current implementation cloud computing. We then present a preliminary model for the implementation an automated system of certification based upon the formalization of contractual rules and consumers' preferences.