When people think or speak of the cloud they are typically meaning a service like "icloud".
The "cloud" has been around since AOL, if not before. Any time a photo gets posted to Facebook,
Picasa, Flickr, or DeviantArt that's cloud computing. All a "cloud" is, is a server holding
data so that the data can be accessed from anything, or anyone securely from any where.
Having said that there are multiple ways to cloud compute: