I know the question in the headline of this post might seem like anathema to a whole host of Mac and Windows fans, who treat their operating systems the same way some people treat their religious beliefs (namely, as something to argue incessantly about). But C.K. Sample asked the question over at the O’Reilly blog, and it’s one that has occurred to me more than once over the past year. There will likely always be people who need a specific operating system, because certain software or tools they use at work will only function with that OS, and there will always be people who prefer one over the other. But for my own purposes, the operating system has become almost irrelevant.

I used to use a Mac for work years ago, then switched to Windows (and before either of those, I used an Atari 1040ST). At home, I used Windows up until a year or so ago, when I switched to Ubuntu. I have a box running Ubuntu and one running XP side-by-side, just in case there’s an app I want to try that only runs on Windows. And if I could convince my chief financial officer to approve it, I would probably buy a Macbook and run Parallels, so I could have two operating systems side-by-side. But in the long run, it doesn’t really matter to me what the OS is, since virtually everything I do involves the Web.

Obviously, not everyone is in the same boat. I write for a living, which requires little more than a text editor. But even the other things that I used to depend on a specific OS for — email, calendar, more elaborate document editing, etc. — are now accomplished through Google (or Zoho). I’ve even started using the online photo-editing app (Picnik) that is now built in to Flickr for editing my pictures, rather than doing it on the desktop with Photoshop or the GIMP. My photos and other documents are backed up through Flickr, Google and Amazon’s S3, so I can get to them whenever and wherever I want, regardless of what computer I’m using. Why do I care what the OS is?

AllFacebook is reporting that Facebook has now made it even easier for developers to create Facebook apps and widgets that will run just about anywhere on the Web. According to the description at ZDNet, developers have been able to get Facebook widgets to run elsewhere since the platform launched, but it took some server-side scripting and knowledge. Now apparently all it takes is a little bit of Javascript.

Whether you think this is a good thing or not probably depends a lot on your view of Facebook widgets and apps, but what I find interesting is how Facebook is trying to straddle the line between control and the open Web — to find some middle ground between the “walled garden” approach and the totally open. The site would no doubt really like it if everyone who created an app used it only on the site, and every user of that app had to come to the site to use it. At the same time, however, Zuckerberg and his team have to recognize that’s probably not going to happen.

Can Facebook continue to be a kind of gatekeeper of the social graph, and yet still allow bits and pieces of its platform to live elsewhere on the Web? I think the fact that it is even trying to do so is worth noting — even though it seems like the site is trying to have its cake and eat it too.