It is a style of computing where massively scalable information technology-related capabilities are provided to users as a subscription-based or pay-per-use service that is accessible in real time over the Internet to multiple external customers. It can extend the existing capabilities of an IT department and provide significant economies of scale. Most organizations that are currently accessing the cloud are using it to supplement their existing IT capabilities. In time, many may choose to move all of the computing needs to the cloud.
Cloud computing allows companies to avoid up-front infrastructure costs and allows organizations to focus on their core businesses instead of spending time and money on computer infrastructure. Cloud computing allows enterprises to get their applications up and running faster, with improved manageability and less maintenance, and enables IT teams to more rapidly adjust resources to meet fluctuating and unpredictable business demand.[ Cloud providers typically use a "pay as you go" model.
Amazon, through its Amazon Web Services (AWS) division, is the dominant player in the space. Other significant competitors include Microsoft, Google, IBM, Salesforce Dell and Rackspace.