Cloud computing is a style of computing in which dynamically scalable and often virtualized resources are provided as a service over the Internet.
Cloud computing can be confused with:

1. grid computing—”a form of distributed computing whereby a ‘super and virtual computer’ is composed of a cluster of networked, loosely coupled computers, acting in concert to perform very large tasks”;
2. utility computing—the “packaging of computing resources, such as computation and storage, as a metered service similar to a traditional public utility such as electricity”;
3. autonomic computing—”computer systems capable of self-management”.