Cloud computing

User Perspective: involves some of the following goals of technology and business:

Server consolidation and asset efficiency
Migration to an industry-standard X86 hardware architecture
Speeding up the provisioning of servers and storage
Reduction in capital expenditure
Enabling a more mobile workforce
Vendors Perspective is a framework or methodology of dividing the resources of a computer into multiple executions environments by applying concepts or technologies. Examples include hardware and software partitioning, time-sharing, partial or complete machine simulation, emulation and quality of service.
Technology Perspective: enables IT, groups, to deploy and manage resources as logical services instead of physical resources. Using network virtualization, IT administrators can segment and align IT services to meet the specific user and group network needs. Logical, secure segmentation helps IT comply with regulations for resource specific security.

Virtualization: Abstracts compute services away from their physical hardware and allow them to be treated as data.

Cloud: Builds on this abstraction by allowing services to be flexibly sourced from a number of providers and delivered over a number of channels.

Asset Efficiency: resulting savings from buying, housing, and supporting fewer devices, (a.k.a benefit of Virtualization)

Strategic Drivers 

Programmers are no longer able to take advantage of this much power with conventional programming techniques. This was earthshaking news back in 2005 when it seemed that programmers would all have to be retrained, or the new hardware would remain underutilized. Applications increasingly need to be concurrent in order to fully exploit the continuing exponential CPU throughput gains. Concurrent programming is complicated, subtle, and requires both training and experience.
Virtualization allows us to keep these incredibly fast machines busy with programs written by normal programmers without these specialized skills. In large part, this factor is what is behind the recent acceleration of virtualization.