With more and more focus on cloud computing one theme seems to be running consistently: the "cloud" is public, and anyone who claims to be building a "private" cloud, a.k.a. mini-cloud or enterprise cloud, is just doing it wrong.

John Foley @ InformationWeek has it mostly right when he says that what's important is the technology.

Focusing on what you call your compute environment based on whether it's public or private seems a bit silly. There are some who try to elucidate the difference between "grid" and "cloud" computing, and do manage to make a technical distinction between the two.

Given that definition there are enterprises engaged in building their own mini-clouds: private, real-time on-demand data centers that service only one entity (the organization) with potentially many customers (business units).

"Private" clouds employ metering (chargebacks), rely heavily on multiple forms of virtualization, and provision resources in real-time using an on-demand model. That's a cloud as much as it is a grid.

Like SOA, it's not as if there's some certification board that's going to tell you that you're doing it "wrong", or "right" for that matter. SOA, grid, cloud - it's all about meeting the needs of the business in an operationally and financially efficient way. If that means a private cloud, than that's what you build. If that means using a public cloud, that's what you use.

Cloud computing is no more required to be public than any other computing model. It's just that - a model - and where it is implemented is of no consequence.

Besides, I thought part of cloud computing was that we weren't supposed to care about location anyway.