Web as Operating System
Kottke make a great case for the web as the next operating system here
Compared to “standalone” Web apps and desktop apps, applications developed for this hypothetical platform have some powerful advantages. Because they run in a Web browser, these applications are cross platform (assuming that whoever develops such a system develops the local Web server part of it for Windows, OS X, Linux, your mobile phone, etc.), just like Web apps such as Gmail, Basecamp, and Salesforce.com. You don’t need to be on a specific machine with a specific OS…you just need a browser + local Web server to access your favorite data and apps.
It raises one of the major obstacles facing the idea of Web as Operating System – Lameness
One thing that might deter you from writing Web-based applications is the lameness of Web pages as a UI. That is a problem, I admit. There were a few things we would have really liked to add to HTML and HTTP. What matters, though, is that Web pages are just good enough.
With the introduction of ifthen YubNub could be a solution to the “lameness” of web pages as user interface.
Just as using CSS allows separation of the content from the presentation, Yubnub allows separation of the interface from the application.
This allows for the hypothetical “WebOS” to have the advantages without suffering from “lameness”