Cloud computing is usually defined as a type of computing that relies on sharing computing resources rather than having local servers or personal devices to handle applications. The Cloud can be thought of as a metaphor for the Internet. So cloud computing is basically a type of Internet based computing where different services are delivered to an organization through the Internet.
Cloud computing is also similar to grid computing, a type of computing where unused processing cycles of all computers in a network are harnessed to solve problems too difficult for a stand alone machine.
The purpose of cloud computing is to apply high performance computing power to perform trillions of computations per second in consumer oriented applications. Examples of this include financial portfolios, delivering personalized information, to provide data storage or to power large, and create and deliver immersive computer games.
In order to do this, cloud computing has networks of large groups of servers running low cost consumer PC technology with special connections to spread data across them. Virtualization techniques are used to maximize computing power.
Since there are currently no standards for connecting the computer systems and software necessary to make cloud-computing work, companies are able to define their own cloud computing technologies. Most are based on open standards and open source software that link together computers.
Cloud computing has become more popular in recent years, and has obtained mass appeal in corporate data centers because it enables them to operate like the Internet through enabling computing resources to be accessed and shared as virtual resources in a secure and scalable way.