Why would an enterprise choose to go cloud computing?

Why would an enterprise choose to go cloud computing? Mr. George Hamilton of Yankee Group has said it beautifully in his June article: cloud computing can fulfill the wishes of “democratize IT, enable enterprise mobility and deliver a more consumer-like technology experience”. It is not the question of why but when, when is the best time to implement the coming trend in cloud computing platform. The whole purpose of the MBA System is to free the organization from the traditional boundary of maintaining a heavy cost and control on IT, to get the system available anywhere and to allow others to be part of the system, including owners, employees and customers. We have been building the MBA System since 2005 based on the belief that mobility will be the most important thing that is coming.