Azure

What is Windows Azure?
Windows Azure is Microsoft's operating system for cloud computing. 
As with other technologies for cloud computing, Windows Azure is intended to simplify IT management and minimize up-front and ongoing expenses. To this end, Azure was designed to facilitate the management of scalable Web applications over the Internet. The hosting and management environment is maintained at Microsoft data centers.
Windows Azure can be used to create, distribute and upgrade Web applications without the need to maintain expensive, often underutilized resources onsite. New Web services and applications can be written and debugged with a minimum of overhead and personnel expense. New capabilities can be added "on the fly" to existing packaged applications.
The Azure operating system is the central component of the company's Azure Services Platform, which also includes separate application, security, storage and virtualization service layers and a desktop development environment.
A feature called Automated Service Management facilitates application upgrading without compromising performance. Functions such as load balancing, caching, fault tolerance and redundancy are included to ensure high availability.

Windows Azure supports a wide variety of Microsoft and third-party standards, protocols, programming languages and platforms. Examples include XML (Extensible Markup Language), REST (representational state transfer), SOAP (Simple Object Access Protocol), Eclipse, Ruby, PHP and Python.
Windows Azure was codenamed "Red Dog" and was temporarily called "Windows Cloud" when first announced, in October 2008.