Nothing has caused as much hyperbole as "The Cloud". But it is here. There isn't much to it. All it means is that data-centers are storing information that you need, rather than on your own Personal Device (ie. PC).
In a way it is a return to the old Mainframe/Terminal days=DataCentre/Personal Device.
My fav cloud App is Tune-In on the iphone. With this app I can listen to all the radio & internet stations around the world and record it if I want to. There is stuttering and the sound quality isn't as good as CD, but hey what a choice I have. Perhaps it truly isn't a cloud product but it is pretty close.