What Exactly is Cloud Computing?

I was lying in bed this morning, feeling just a little guilty for not turning out the lights last night between 8:30 and 9:30, thinking about the clouds – cloud computing that is. When I checked my email this morning I had an email from a member in a network I belong to that is stuck in Seattle because of the Ashes shot 50,000 feet into the clouds by Mount Redoubt the volcano in Alaska. He is looking to get himself and seven friends a chartered flight to Valdez! Not sure why a charter flight would go if the commercial flights are not as is implied in the email…….

Anyway, I was thinking about several articles I read about cloud computing last week that have discussed the meaning of the terms and the evolution from application service provider (ASP) to software as a service (SaaS) and hardware as a service (HaaS). There was discussion on how these models changed but I struggle with this because these are all terms to describe different parts of Cloud Computing. The models have evolved and terms like ASP have become passé but the terms still essential describe the same kind of service. The term cloud computing is all encompassing – from hosted email to Facebook it is all in the cloud. So I looked it up on dictionary.com:

Main Entry: cloud computing
Part of Speech: n
Definition: a type of computing based on sharing computing resources rather than having local servers or personal devices to handle applications

Example:
Cloud computing has started to obtain mass appeal in corporate data centers as it enables the data center to operate like the Internet.

Webster's New Millennium™ Dictionary of English, Preview Edition (v 0.9.7)Copyright © 2003-2009 Dictionary.com, LLC Cite This Source

So when I first read this I thought “no this is wrong” but on reflection this is correct! However, I think today when you discuss cloud computing we mean computing in any form over the internet not like the internet!

So I went to wikipedia:

From Wikipedia, the free encyclopedia

Cloud computing is Internet ("cloud") based development and use of computer technology ("computing").[1][2][3] It is a style of computing in which dynamically scalable and often virtualised resources are provided as a service over the Internet.[4][5][6][7] Users need not have knowledge of, expertise in, or control over the technology infrastructure "in the cloud" that supports them[8]
The concept incorporates infrastructure as a service (IaaS), platform as a service (PaaS) and software as a service (SaaS) as well as Web 2.0 and other recent (ca. 2007–2009)[9][10] technology trends which have the common theme of reliance on the Internet for satisfying the computing needs of the users. Examples of SaaS vendors include Salesforce.com and Google Apps which provide common business applications online that are accessed from a web browser, while the software and data are stored on the servers.
The term cloud is used as a metaphor for the Internet, based on how the Internet is depicted in computer network diagrams, and is an abstraction for the complex infrastructure it conceals.[11]

Well in my humble opinion Wikipedia has it right – not that Webster was wrong but not as in touch with today’s cloud computing world and I suppose the evolution of the meaning of this term!