Of course everyone who uses computers knows what importance does an operating system holds in making a computer a usable piece of engineering. Without an OS a computer would be very difficult to be used for any task by a common man.
The Operating system provides a layer above the internal hardware of your computer and you. It acts as an interface between you and computer machine so that your commands can be easily understood by your computer. The OS provides a platform to run various application on your computer which otherwise would have been impossible in your computer to run. The other way of considering the same scenario is that if you don't have a standard operating system in your computer then the application that you are using right now in your computer need to have the system software capabilities. This would require all the applications to be almost an operating system in order to run in your computer.
Just imagine, how difficult it would have been for the people to develop applications then? Each application needs to have a layer of codes written that would interact with the hardware of your PC. If you have got an Operating system explicitly to interact with the hardware of your computer then developers don't need to build these human machine interfacing feature in their application. SO now, a lot of time, energy and resources are saved when you have an OS sitting on top of your computer hardware to have all other applications site over itself.
Now you only concentrate on developing the core functionality of your application and not on the OS capabilities to make it run on any PC. If you can understand this concept you can understand the Web OS - Web Operating System concept also. Actually, the Web OS is a platform to run some similar kind of application on the browser. If you try to understand this concept with a developer's perspective you will know what I mean.
If you want to develop a new shopping site you can use the framework of tried , tested and already industry standard application like Amazon. You can use the framework of Amazon shopping site to have a website build over it which would have a solid architecture and you would not need to focus on the developing your shopping site from the scratch. So now, a layer above the www sits, where people who want to build Shopping site can have the API's and framework of Amazon to develop their custom sites. Same thing can be done for search engines using Google's APIs, portals using Drupal's framework, social networking sites using facebook framework and likewise the whole new application would use the industry standard application's framework or APIs to have their business supported by a solid technical architecture imposed by such proven and industry standard application saving the new business's valuable time, energy and money.
