First, the article.

Second, the salient quote so that you don't really have to read said article:

"If you are getting any benefit from Microsoft's software, you need to have a license, whether that benefit is for physical machines or virtual machines," Voce said in a session titled "Microsoft Licensing in a Virtual World." "You cannot engineer your way around licensing requirements. You can't use the technology as a way to cut corners around licensing."

The question I find myself asking is whether virtualization diminishes the perceived value of the operating system. As I deploy more virtual servers to do more specialized tasks, along with the very useful MTTR benefits of full VM snapshots, the relative value of the OS in that asset decreases. In fact, if I could have a purpose built OS that's completely built around executing the application function I require. Wouldn't that be far better than loading up a full, bloated, operating environment? In this equation, the value of that virtual appliance model far outweighs the value of the separate OS+Application model of the past. In fact, you might even be willing to pay more for the cost of ownership benefits of the virtual appliance (more for less, so to speak).

That's all well and good to think about, but what's the security angle (I hear you saying). Well, ubiquity breeds risk. A larger pool of targets is more attractive. 100,000 Windows based VMs is just as attractive a target as 100,000 physical servers. Purpose built virtual appliances, however, would increase the diversity of the target population. Further, they're purpose built, and we all know that increased complexity results in more bugs (aka, vulnerabilities). What I'm suggesting here, I suppose, is that the open-source community should figure this out before Microsoft because right now there's a clear financial advantage to using a free (as in beer) OS for your multitude of virtual images.