To paraphrase the definition of Cloud Computing from dummies.com:
Cloud computing is the next stage in the Internet's evolution, providing the means through which everything — from computing power to computing infrastructure, applications, business processes to personal collaboration — can be delivered to you as a service wherever and whenever you need.
Cloud services include the delivery of software, infrastructure, and storage over the Internet (either as separate components or a complete platform) based on user demand.
What are the benefits of cloud computing
Cloud computing is gaining widespread corporate acceptance because it overcomes many of the challenges and inadequacies of traditional on-premise software and hardware solutions. Just like outsourcing, lower cost was the initial reason organizations started to shift to cloud-based services, but the reason they stay is because it gives them greater control over their business with less hassle at a predictable cost.
There are four key benefits that companies realize by adopting cloud computing:
No upfront investment of capital -- By utilizing cloud computing, companies are able to take advantage of new technology and immediately leverage software functionality without having to invest personnel resources or tie up valuable capital purchasing expensive hardware and software licenses.
Increased productivity – Services firms, particularly those with fewer than 50 employees, have limited resources available to dedicate to tasks other than obtaining and servicing customers. Cloud computing allows companies to keep their resources focused on growing business, and improves user productivity by increasing application accessibility, reliability and security. With cloud-based services, companies realize a quicker time to value with implementation of new applications taking only days or weeks instead of the months or even years required for on-premise solutions.