There has been lots of talk about a potential Google operating system lately. A web-based operating system is probably more of a convenient way to describe the way Google and the web in general is obsoleting traditional desktop applications and systems than an expression of any tangible product or project.
That said, people love screenshots. Almost all screenshots I’ve seen of mocked-up ideas of what a WebOS might be look a lot like Windows XP. This is understandable as it’s a quick way to say “look, this looks like like your normal computer, but it’s a WEBSITE!”.
Windows (as in little boxes that hold tools, documents, and applications, not as in “Microsoft Windows?”) don’t actually make a lot of sense in web-based applications.
First, desktop operating systems have mature and dedicated “windows managers” that do all of the hard work of actually having those little boxes all over our screens. Sure, a lot of this behaviour can be replicated with fancy web-twenny techniques, but for the most part, it’s not worth it.
Which brings us to the second and more important reason that the WebOS won’t have windows. It doesn’t need Windows. Interface designers have been waiting for the end of the traditional desktop operating system interface (desktop, folders, icons, windows, menus, etc.) since shortly after it was invented. Web applications like Gmail have shown that you can have effective and efficient interfaces without anything like windows that overlap each other.
The browser canvas already lives in a window, often in a tab inside that window. Filling it with another set of windows with a set of behaviour that is similar to, but not exactly like the behaviour of the base operating system windows is likely to create a variety of usability issues.
Rather than a distinct product that looks like Microsoft Windows but lives on the web, I suspect the move to web-based computing will be (and already is) a gradual shift. Web-based mail is a big change that has already happened without the help of any replication of the desktop/windows/icons/menu interface.
Incidentally, MIT One Laptop Per Child interface has done away with the concept of overlapping windows. Each application or document runs full-screen at all times. This is partly informed by the size of the screen on the device, but it also conveniently eliminates an entire mental model required to interact with multiple windows.
All of that said, there was some talk at the recent Firefox Summit about ways to allow Firefox to bring web applications deeper into the desktop. For example, allow a web-application like Gmail to run it’s own process of Firefox that can display status in the system-tray (or dock), respond to system calls (like “open the default email application”), and stay alive even when your web-browser is closed. The idea is that rather than making desktop applications more web-aware (which seems to be the Microsoft Vista approach), we can make web-applications more desktop aware.