What is cloud computing? What is the difference between a cloud and the internet?  Some Twenty-One Experts Define Cloud Computing differently, and there are even more definitions out there. Among many that I've heard are some of the following:

• Cloud = Internet
• Cloud = Innovation
• Cloud = On Demand
• Cloud = Autonomic computing
• Cloud = Distributed computing
• Cloud = Grid computing
• Cloud = Hosting
• Cloud = Multi-tenancy
• Cloud = SOA
• Cloud = Utility computing
• Cloud = Virtualization
• Cloud = SLA-driven
• Cloud = SaaS
• Cloud = PaaS / OPaaS
• Cloud = IaaS / HaaS
• Cloud = Just a marketing buzzword
• Cloud = Applications, Platforms, and Infrastructure delivered as a service

Many also say, "Cloud computing is nothing new.  All of these technologies have existed for quite some time".  That's like saying the iPhone is nothing new because all the technologies existed prior to its arrival.  For an innovative company like Apple, it's great that their competitors lack such imagination, as it leaves the field wide open.

From my perspective, we have not had cloud computing a long time, we've had many of the disparate underlying technologies that are now converging to facilitate what is generally referred to as cloud computing.

Larry Ellison, Oracle's CEO, does an amusing bit on YouTube on the definition of cloud computing.  He calls it nonsense, gibberish, encompassing everything we do today, and generally referring to those that use the term insane, crazy. To some degree, Larry is right.  The technologies have been around for some time.  In fact, in 2003 I worked with a team to create this piece for IBM.  Recognize some of those technologies?  And you can even go further back, much further.

Think of it this way.  Virtualization was around many years ago, on the mainframe, and over time it made its way out of the mainframe, but it was of limited benefit for SME.  On Demand, Autonomic, Distributed, Grid, Utility, Hosting, have also been around for a while.

While all these technologies have been relevant to large enterprises, they remained largely inaccessible for small and medium businesses to leverage due to cost, complexity, and lack of in house IT skills to implement such technologies (with perhaps some exceptions like free hosting).  Generally, the costs outweighed any benefit as small enterprises didn't have the necessary scale to leverage these technologies.

Cloud computing (the convergence of many of these pre-existing technologies), through its service providers, makes these technologies accessible to small and medium business in a simple, cost effective manner, without the need to have a deep understanding of these technologies.  So how is this distinguishable from the Internet?

If you ask lay people to describe the Internet as best as they can, they'll likely mention Google (though probably not the app engine), Amazon (though probably not AWS), YouTube, Yahoo, eBay, Gmail, Hotmail, Yahoo mail, etc. - mainly consumer services.  In short, B2C (or C2C / peer to peer) applications, or if you prefer, Consumer Service Provider to consumer - whether transactional as in Amazon and eBay, or ad supported as in Google, Yahoo, etc. the focus is consumers.

When it comes to Cloud computing, I tend to view it through the lens of business and technology.  So, I may think of it as an, "IP enabled, scalable, virtualized, multi-tenant, subscription based (or "pay as you"), B2B, service delivery method for business software applications, platform development, and adaptive infrastructure". i.e. (SaaS based applications, PaaS based development, IaaS based infrastructure) .

Though for non-IT SMB clients I would simply describe it as, "A subscription based, B2B Internet service delivery method for [business] applications".  Yes, that leaves a lot out, but the clients are not interested in the technology - just in what it can do for them.  The rest, like the iPhone, they take for granted - scalability, real-time, on demand, etc.

When we talk about an iPhone, we don't describe it in terms of technology.  We don't refer to it as a subscription based, IP and application enabled, cellular capable, real-time, multi-service, communications device.  That's the beauty of Apple, always abstracting the complexity of the underlying technology, and therein lies the beauty of the cloud.