How is cloud computing useful?

• Burst compute capacity: An organization has to compute and process a lot of payroll information towards the end of each month. This processing requires compute power; the more the power the faster the results are calculated. Cloud computing can provide such burst compute capacity on demand to its users, when they need it the most. The organization can spin up virtual machines or instances in the cloud, scale them based on the randomness of their demand, and then destroy all the instances once the job is done. This entire process can also be automated to make the entire payroll computation far easier and effective at the end of each month's cycle.
• Dev and Test: A classic use case when it comes to cloud computing is the development and testing of applications and code on the cloud. Organizations can host their development centers on-premises and test the applications on the cloud by spinning up instances quickly, testing on them, and then tearing the entire infrastructure back down when not needed. Massive and complex infrastructure environments can be built on clouds with ease with the use of templates, cloning, and automated provisioning.
• Disaster recovery: A common use case for most enterprises today is to use a cloud as a mechanism for disaster recovery. Organizations create stand-by infrastructure environments on a cloud that can either perform hot or cold migrations on demand. Clouds today use a variety of techniques to achieve this such as live virtual machine replication, templates, and cloning.
• Temporary sites: Similar to the development and test scenario, a cloud can also be used to spin up simple advertising, marketing web sites, or a micro-site for a couple of months. Organizations can easily create and power on entire sites in the cloud, use it for a certain amount of time, and then tear it all down (and save it potentially for later use) once they are done.