Of course "the Cloud" isn't new, but it's so ubiquitous now. Microsoft has taken a word processor as far as it can reasonably go, there's really no reason to keep buying updates to a programme that does everything you need, so there is a logic in giving away the programme and charging for the "Cloud" storage of the documents. I can start editing a document at home on my desktop, work on it on the train on the way to work on my tablet, review it on my phone and finish it on a laptop at work. I no longer care where I am or carry a USB stick. It's there, all the time.
Say you are sitting in Macca's and you suddenly have the answer you need, pull out your phone and edit it right there. It's a loss of control, indeed the loss of the very control that drove the PC revolution. But it's worth the trade off. I just can't see us as a society going back now. My entire 100 gigs of personal photos is there on every device I own or use. My 200 gigs of music, there. My letters, project documentation, etc, there.