A couple of weeks ago Alfresco CTO John Newton posted the following tweet on Twitter:

"Does Cloud = SaaS [Software as a Service]? I don't think so. Cloud is computing, more like electricity."

My gut reaction was that they were equal, and up until that moment I had used the terms interchangeably, but Newton's post got me thinking that perhaps they were different. SaaS applications use cloud platforms, but are not exactly cloud computing. The more I thought about it, however, the less clear it got, so I decided to do some research and also take my questions directly to some cloud computing experts and ask if the two terms were indeed synonymous or if they were as Newton opined, completely different.

Let's Define Terms

SaaS is an acronym for Software as a Service. I've written about this in Does Using GMail Mean You're Stupid? and several other posts. For companies, using a service, it means they no longer have to worry about building an infrastructure for the software. Instead, the software is available via web browser and the hosting company in exchange for your subscription fee, handles all the heavy lifting on the back end. For some companies, it's a very attractive option.

So how does this differ from Cloud Computing? In a Gartner Voice podcast from last summer, Daryl Plummer, managing VP and chief Gartner fellow offered this view of cloud computing:

"Someone is going to take responsibility for delivering some IT-related function as a service to a set of customers. Now, these customers don't even have to know how the service works. They just get to use it."

That sounds a lot like the service and the infrastructure are linked, but Plummer goes onto say that the true power of cloud computing lies in the way it changes the economics of computing, that is that it creates a marketplace with service providers and consumers. "The way that we actually charge for those services won't necessarily be based on how many servers we're running, or how much maintenance costs or which software products we bought. It's going to be based on the value of the service to the customer, and when you start getting into that consumer-provider relationship, the customer sets the value. It's what the market will bear."

If you think about what Plummer is saying here, this sounds a lot like Newton's idea of computing as electricity.

Saleforce.com: The SaaS and Cloud Computing Vendor

I decided to ask Salesforce.com mostly because they are the prototype SaaS vendor, and at the same time, they now have Force.com, a cloud platform for building your own applications on the same platform Salesforce.com runs on. Al Falcione, Saleforce director of product marketing sees a fundamental difference between the two concepts. "We see cloud computing as a very broad term that refers to building and running applications on the internet."

He says within cloud computing, Salesforce sees two different markets: cloud computing platforms like Salesforce, Google and Amazon upon which applications are built. But he says, "cloud computing applications are for lack of a better term, packaged applications that run in the cloud." Saleforce.com and Clickability are two examples of this, as are Gmail and Google search.

Jan Allerman, CEO at Servoy, a company that runs an application development environment as a service, says the line between the two terms can get thin. "Strictly speaking, the SaaS would be the service and cloud computing would be the computer layer running on the internet." He says Force.com sits in between that by providing a development environment and putting it inside their cloud to do hosting of that service.

While I see the nuance, I have to conclude that Newton's post is essentially correct. The two terms are different and SaaS to a great extent is a subservice of cloud computing. Not all cloud applications are SaaS applications, but essentially all SaaS applications are in the cloud, and the cloud is strictly providing the computing power to run those applications, regardless of the type.

What do you think? Are they the same or different?