Cloud computing is the delivery of computing services—including servers, storage, databases, networking, software, analytics, and intelligence—over the Internet ("the cloud") to offer faster innovation, flexible resources, and economies of scale.
Infrastructure as a Service: Provides virtualized computing resources over the internet.
Platform as a Service: Offers hardware and software tools over the internet, typically for application development.
Software as a Service: Delivers software applications over the internet, on a subscription basis.
Services offered by third-party providers over the public internet.
Cloud infrastructure operated solely for a single organization.
Combination of public and private clouds, allowing data and applications to be shared between them.