The
Cloud-Computing concept first gained public attention in
1960, when Boston-born computer scientist and Turing Award winner
John McCarthy noted that "computation may someday be organized as a public utility." Since then, the concept has undergone a series of metamorphoses, touching on everything from service bureaus and application service providers.
Today, cloud computing has taken over as the primary metaphor, and is commonly described as including three areas: Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS) and Infrastructure-as-a-Service. For a fast-growing number of businesses, cloud computing is now the dominant choice of IT technology for running business applications.