computing paradigm in which tasks are assigned to a combination of connections, software and services accessed over a network. This network of servers and connections is collectively known as "the cloud." Computing at the scale of the cloud allows users to access supercomputer-level power. Using a thin client or other access point, like an iPhone, BlackBerry or laptop, users can reach into the cloud for resources as they need them. For this reason, cloud computing has also been described as "on-demand computing."
One of the more dramatic changes is a shift to cloud computing -- where applications and files are stored on a large, centralized supercomputer or network. The end user accesses his or her files using computers that are more streamlined but less sophisticated than today's typical machines.
Cloud computing comes into focus only when you think about what IT always needs: a way to increase capacity or add capabilities on the fly without investing in new infrastructure, training new personnel, or licensing new software. Cloud computing encompasses any subscription-based or pay-per-use service that, in real time over the Internet, extends IT's existing capabilities.
From the above definition it is clear that Cloud Computing is delivering Software as a Service (Saas). Move everything into server and access from the any endpoint interface. Analysts predict that the future will be about doing everything on the cloud without worrying much about the client.