When I was studying network engineering, "the cloud" used to encompass the broader network environment that INCLUDED the Internet as an extension of your enterprise infrastructure. Now? It's a hyperbolic, singular phrase that is limited to using the internet as an extension of your operating system without fully explaining or at least detailing for the end user why it matters.
Especially in the case of those god.awful Microsoft commercials. In their case, the way it's presented, the cloud is nothing less synonymous with social networking. Change your Facebook status from Windows? That's the cloud. Upload a picture to Flickr? That's the cloud. It's no better than that phase of 'web 2.0' that was nothing more than superficial design elements that included shiny buttons, dropping vowels and slapping the term 'beta' on everything. The web is cyclical and this is the latest cycle.
While that in and of itself isn't BAD per se, it's a phrase that's come synonymous with "rockstar" and "ninja" when talking about hiring developers. A total and complete non sequitur.
Any way I try to define it(other than how CNN puts it) I end up leaving out a huge chunk of cos that also claim to be into cloud computing. And I am not exCtly sure if anyone is in a position or authority to tell them "no you've got nothing to do with the cloud".
And secondly, like it or not, it is nothing new - not even a new concept. See e.g. grid computing and what Foster et al. describe as "utility computing" in their vision; it makes cloud computing look more like a sub-category.
I have the same feeling about "web 2.0" - it was merely "normal people" catching up with the tech savvy crowd on a large scale.