Michael Rees's List: The Cloud and You

"The NIST Definition of Cloud Computing publication SP 800-145"
Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction

Cloud computing, or something being in the cloud, is an expression used to describe a variety of different types of computing concepts that involve a large number of computers connected through a real-time communication network such as the Internet.[1] Cloud computing is a term without a commonly accepted unequivocal scientific or technical definition

"Ask a simple question and be prepared to open a can of worms, especially when that question is 'What is this thing called cloud?' The term cloud computing has been used a lot lately to describe a myriad online services, as well as additional computing capacity that resides somewhere out there. Defining it is tricky but not impossible."

The security challenges cloud computing presents are formidable, including those faced by public clouds whose infrastructure and computational resources are owned and operated by an outside party that delivers services to the general public via a multi-tenant platform.