Yes, a web based OS could be a reality in the very near future.

Quote: Originally Posted by TechSpot YouOS Demonstrates a Web Based Operating System What's the next step after web-based applications and thin clients? Web-based operating systems, apparently. An interesting idea known as YouOS is a project that strives to create a full computing environment that is entirely web-based, running programs (including browsers) completely inside your browser. Files are saved and data kept inside your virtual web environment and you can access it from just about anywhere. While not much more than a demo at this point, the concept and potential behind YouOS is clear. As long as you can access a browser, you could theoretically access your YouOS machine. With many companies focusing on creating web-based applications, even Microsoft, the near future may see projects like this become commonplace. Take a look

New Source: TechSpot