There’s an interesting debate raging over at Focus.com (a newly formed site that is dedicated toward facilitating the sharing and exchange of information as well as provide access to subject matter experts). The question was posed, “Is Facebook a cloud?” Clearly, there’s differing opinions on the response to this question, which makes for good reading and opens the door for discussion. Incorporated into this question is a underlying skepticism that I addressed in my entry, Scale is the Common Abstraction of Cloud Computing, which is does Software-as-a-Service (SaaS) really belong within the definition of cloud computing?

Let’s use Facebook as the reference model for answering this question. As I posited in the discussion at Focus.com, how Facebook chooses to implement their application is mostly irrelevant to us as a consumer of that application. To make assumptions about their application’s architecture or to incorporate knowledge from interviews and articles about how Facebook works into our decision to call Facebook cloud acts to introduce irrelevant information into the discussion. To incorporate SaaS or any application under the moniker of cloud merely begs the question of the value of the term to the industry and the role marketing is playing on formulating this industry.

Indeed, SaaS by the nature of what it is should relish the abstraction of itself from its implementation. After all, what they’re selling customers is their ability to provide a highly-available and easily accessible application. Now, as I also posited in the Focus.com discussion, Facebook also provides a platform for authenticating users and authorizing access to their data. This component of Facebook I would be open to incorporating into the cloud discussion under the moniker of Platform-as-a-Service (PaaS). However, due to ambiguity, to blindly state that Facebook is cloud without clarifying that you are discussing the PaaS component of Facebook would leave one to believe that you are discussing the SaaS component of Facebook, which I would continue to argue does not belong to the class of things that are incorporated under the cloud moniker.

I have danced around this topic for some time now, but this discussion finally pushed me to come out against including SaaS in the definition of cloud computing moving forward. Software-as-a-Service is merely a consumer of cloud computing and not a component of cloud computing. Or, as we like to say in the architecture world, SaaS uses cloud, not SaaS is a cloud. Hence, the Facebook application is not cloud.

I realize there’s going to be a lot of unhappy campers who read these words, but having written an entire book on semantics and ontology, I would be remiss if I did not raise my hand up and say that we need some aspect of rational thought about what’s in the cloud class and what’s outside the cloud class. Now, since no one group or person officially owns the definition of cloud computing, SaaS vendors will most likely to reject this entry and continue to stomp all over the term in favor of being included in the class of “what’s hot”, which is most likely the root cause for Larry Ellison’s statement that the computer industry is more fashion-driven than women’s fashion.