Cloud Computing: A Simple Description:-

In its most simple description, cloud computing is taking services ("cloud services") and moving them outside an organizations firewall on shared systems. Applications and services are accessed via the Web, instead of your hard drive. In cloud computing, the services are delivered and used over the Internet and are paid for by cloud customer (your business)  -- typically on an "as-needed, pay-per-use" business model. The cloud infrastructure is maintained by the cloud provider, not the individual cloud customer.

Cloud computing networks are large groups of servers and cloud service providers that usually take advantage of low-cost computing technology, with specialized connections to spread data-processing chores across them. This shared IT infrastructure contains large pools of systems that are linked together. Virtualization techniques are often used to maximize the power of cloud computing.

Currently, the standards for connecting the computer systems and the software needed to make cloud computing work are not fully defined at present time, leaving many companies to define their own cloud computing technologies.