Cloud computing refers to the utilization of shared, elastic resources and processing power accessed via the Internet. In some ways, it hails the reversion to the golden age of time-sharing but with significant improvements to the distribution philosophies underlying the delivery infrastructure. [...] Cloud-based development involves in some sense, the outsourcing, of various parts of the application out of the server and into the cloud.

Included is an illustration of how an application would interact with the cloud and an example of working with the S3 service that Amazon offers. The example mentions both the normal services and something called the "elastic compute cloud" that lets you use remote services to run virtual instances of other operating systems.