It's hard to precisely define cloud computing. As I see it, it's having data and programs distributed on the Internet so you don't have to worry about where they are located; you just have to know how to get to them. The best example I can think of for cloud computing is Google Docs, where you can get free online word processing and spreadsheet functionality. (I highly recommend this, by the way.)
This web site itself, created with Google Sites, is an example of something created with cloud computing. The pages are created entirely online, and nothing is saved to my local disk drive in making this site. Therefore nothing has to be uploaded. As soon as a page is created (or changed) and saved, it's live.
It occurred to me recently that for years I've been using cloud computing to play chess with others around the world.