Yesterday, Microsoft completed its purchase of a little company named Softricity. It’s an interesting acquisition, one that sheds a little more light on the virtual future of information technology.

Softricity was born in Boston’s Computer Museum a decade ago. Three guys were putting together an exhibit on kids’ software and had to figure out a way to deliver a bunch of applications – mainly games – to a dozen or so PCs and let children fool around with them without screwing up the systems. They developed a way to, in effect, stream the applications over a network, downloading bits of code as required to the desktop machines and running them in a “virtual container” that shielded the underlying operating system. The technology became the basis for Softricity’s core product, SoftGrid, an application virtualization system that allows you to stream any Windows application to a bunch of PCs or thin-client terminals over a network.

Microsoft has had a partnership with Softricity for a while, but the acquisition points to something bigger. Most obviously, Softricity’s technology will help Microsoft better respond to companies’ growing desire to centralize the provisioning of desktop applications in order to reduce the burdens of maintenance, upgrading and troubleshooting (and in the process trim their IT staffs). When you stream an app, everybody gets the same version in the same configuration – and their core system remains untouched. Desktop maintenance issues go away, and upgrading becomes a snap.

Second, the technology may help Microsoft sell (or give away) a range of applications – or even entire desktops – as services that customers can subscribe to. That would be a different take on software-as-a-service, because the applications could be traditional ones – the same ones you used to have to install on your own PC. Also, because Softricity’s system caches code on the client machine, you’d have the ability to run the apps even when you weren’t connected to the Internet, an important advantage for mobile workers. You can already stream audio and video over the Net. Why not stream applications as well?

Of course, there’s also a defensive reason behind Microsoft’s acquisition, as well as its other recent virtualization initiatives (including its linkup, also announced yesterday, with XenSource, the supplier of open source virtualization software). If your products are going to be virtualized, it’s better if you’re doing the virtualizing rather than a competitor.