The Cloud: Why should we care?

"Telling consumers their data is in the cloud is like telling a kid his dog has gone to doggie heaven." Best Quote from Cloud Control June 20, 2011 Time Magazine Vol. 177 No. 25 Article

What is this cloud thing? Is it another new fangled fad  fleeting about in the firmament only to burn out as more people discover it's just a fancy figment of some marketers imagination?  AI and TQM come to mind as fads that faded because the promises where greater than reality. But a lot of serious technologist feel it's a concept that is here to stay.