Cloud techonlogy is a relatively new business model in the computing world.
It doesn't matter if you are a technology wizard or a non-tech business professional. Cloud computing is impacting your job, and the ability to be savvy with cloud resources can mean career advancement. For business professionals, it means better understanding information technology. For IT professionals, it means better understanding the business.
The "Cloud computing" term was coined in 2006, when Amazon decided to "lease out" (give at external system/organizzation the possibility to use Amazon resources with a periodic payment) this gear to try and recuperate some costs. They lauched theri Elastic Compute Cloud (EC2) services that enabled oraganizzations to "rent" computing capacity and processing power as a utility on which to run their enterprise applications. Other large IT companies with massive computing resources quickly joined that market (Google, Microsoft, VMware, Red Hat etc) and that brings us where we are now.
Numerous reasons drive companies to explore or adopt cloud computing services, with the primary reason being cost. Small companies and start-ups can't afford a large amount of hardware, with cloud computing this is possible.
Many companies realize that many of their IT resources sit idle for infrequent usage peaks. This is the driver to adopt a "pay-for-use" model. Renting resources (hardware or services) have more sense than purchased IT hardware because you know that IT hardware alway goes down in value, never gains value.
Cloud computing is the result of the convergence between some business drivers and several technology innovations. Example of business drivers are capacity planning, cost reduction and organizational agility. Example of technology innovations that made cloud computing a reality are: clustering, grid computing and virtualization.
Clustering means to create a failover system that employs multiple similar IT resource together to provide greater availability and reliability in case one resource fails. Clustering improves resiliency, which is a key charactieristics of cloud service.
Grid computing is a way to provide computing resources on demand and on pay-as-you.
The creation of virtualization software has enabled physical IT resource to provide multiple virtual images of themselves so their overall capabilities ca be shared by multiple users (tenants).