An example from the recent past demonstrates just how much can come from the cloud today. Billions of people ­wanted to ­participate when the new American president Barack ­Obama was inaugurated into office in January. The ceremony was streamed live onto the Internet and watched by hundreds of thousands. A great number of hobby journalists used mobile devices to write their experiences in their Facebook and Twitter blogs, a kind of “voter-generated content”, so to speak. Countless cell phone users reported on the event to their families and friends.

Events of such a large scale represent an enormous challenge for those responsible for ICT operations. For example, in preparation for this historic occasion, AT&T had to invest millions of dollars to increase the capacity of its mobile network in the Washington area by 80%. Would it not be wonderful if the peak loads caused by such large events or, taking another example, widespread advertising campaigns could be absorbed by hiring the ICT resources when and where needed – and naturally with payment according to actual use? This is where cloud computing comes in. Cloud computing makes it possible to hire ICT infrastructures and applications temporarily and to pay for them according to how much they are actually used. Whenever there is a surge of users – as during Obama’s inauguration – more resources are provided automatically, and then closed down again when the storm has passed.   

Lifting the cloud cover – an attempt at a definition

But just what is the term “cloud computing” supposed to mean? A number of vague buzzwords related to the idea are making the rounds, but their precise meaning and their relationships to one another are not always clear. So let us attempt to lift the heavy cloud cover and come up with a definition of the term.