Cloud computing is not a stand-alone technology, but rather a mix of a large set of various technologies. Although based upon previous trajectories, recent progress in virtualization, storage, connectivity and processing have come together to create a new ecosystem. The result is a new paradigm extremely attractive from an economic perspective due to its capability to combine cost saving with increased flexibility to manage the ICT needs of firms. The main characteristics of cloud computing are as follows: High degree of abstraction of the user from the physical and technological characteristics of hardware and other related ICT infrastructure. Easily adaptable: its use and cost can be adjusted to demand changes without specific contracts or penalties. Multitenancy: cloud architecture allows firms to access ICT infrastructure while ensuring privacy and security. Pay-per-use: user cost varies based on actual consumption.