To best capture the primary value of Cloud Computing I always recommend looking at the scenario of a new entrepreneur launching their online business.
The Cloud has made entrepreneurism itself more accessible to more people, lowering the barrier to entry by lowering the costs it takes to launch a new online venture by a magnitude, while simultaneously improving the quality of the apps you can produce, and how quickly you can produce them.
Combined with the continuing explosion of online users and how much they grow their daily use of social media, e-commerce etc., this is a massively potent combination.