Cloud computing is Internet-based computing where resources are offered on demand, much like the electrical grid we all share. This is a new delivery and use model for IT services based on the Internet. 

Supporters of cloud computing have reasons for their ardor:

• Pay-as-you-go subscriptions mean lower costs and software tailored to your needs
• Decrease in software maintenance since the programs are housed in the clouds, not your hard drive
• Increased reliability from stable cloud systems means less down time, and higher productivity
• Dynamic scalability because you’re not chained to a hard drive
• Overall cost reduction from various sources – for example, reduced IT staff since the service provider takes care of maintenance
• Environmental friendliness because now organizations are able to prolong the use of older hardware which means a lower carbon footprint
• Matching trends in computing as less powerful and more efficient platforms move in that can use cloud processing
• Grid computing means greater availability and productivity wherever an active internet connection exists
• Efficiency through virtualization allows multiple server technologies to run from a single server
• No more software upgrade projects because the cloud would offer enterprise wide updates and releases