One of the things that irks me is when somebody talks about any one application as a "WebOS".  It shows a fundamental lack of understanding about the way operating systems work and a willingness to regurgitate any misapplied marketing fluff that a company wants to attach to their product.

I'm going to pick on Read/Write Web here a little and use their definition of a WebOS as an example:

"Firstly, let's revisit what a WebOS is. A WebOS is a web-based app (generally powered by either AJAX or Flash technologies) that emulates the application capabilities of an operating system. It's basically a virtual desktop that gives you communication tools (like email and instant messaging), productivity tools like word processing, and ability to play games and any other application that you'd find on a typical OS like Microsoft Windows."

(Emphasis mine).  Ok, let's focus on that contradiction.  What is being called a "Web OS" is not an operating system, it is an application.  Applications run on operating systems, they are not themselves operating systems.  These things that are being called "Web OS's" are the exact same things as the Web desktop applications that have been around for years now such as NetVibes, PageFlakes, and Goowy.  These are not operating systems, they are applications with API's, that run on top of REAL operating systems.  Unless you're prepared to call every application that allows applications to be built on top of it an operating system, please stop.  The list would be gigantic, and the term "operating system" will become meaningless.  A service-oriented architecture does not equal a Web operating system.

Now, if you want to know what a REAL operating system is, let's see what Wikipedia has to say:

"An operating system (OS) is a computer program that manages the hardware and software resources of a computer. At the foundation of all system software, the OS performs basic tasks such as controlling and allocating memory, prioritizing system requests, controlling input and output devices, facilitating networking, and managing files. It also may provide a graphical user interface for higher level functions."

Under this definition, I don't think you can realistically call any of these so-called "WebOS" applications "operating systems".  It just dilutes a perfectly useful word.

Now, what I WOULD call a Web operating system are the services that do the things that are typically handled by the operating system.  More along the lines of cloud computing--taking the place of (real) typical operating systems such as Linux and Windows that actually run the Web-based applications we use.  Here are a few that I can think of off the top of my head:

• Amazon S3 - Provides online storage capabilities to applications
• Amazon EC2 - Provides cloud computing services to applications, scalable as needed
• Amazon Simple Queue Services - Provides cloud message queuing capabilities to applications
• Google Base Data API - Allows applications to store data in a quasi-database
• Google Data API - Provides data syndication capabilities to applications
• Dojo and Prototype - Provide applications with a flexible user interface layer

As you can see, you'd pretty much have to stitch together a bunch of different services to arrive at a "real" Web operating system.  And Amazon seems to be in the lead as far as providing a complete suite of Web operating system components.  However like the Web itself these services are decentralized and not based on a single application, unlike these so-called "Web OS's".

I think we're still a couple years out from being able to usefully talk about a "WebOS", and when we do I think it's going to be talking about the Web as a whole, not any particular application.  It'll be more along the lines of a concept we've been giving lip service to for a long time:  the network IS the operating system.