Webian Shell is a full screen browse that completely takes over your desktop so give you an uninterrupted online experience. When you are online in the app, there is no chance of being distracted by other running programs as they are simply not visible - you are left to focus solely with what you want to do online. Webian Shell sits on top of your current operating system, but it may as well be a simple OS in its own right.
As a browser, there are few surprises. Webian Shell offers tabbed browsing in much the same way as all modern browsers do - the difference here is that the tab appear that the bottom of the program window rather than at the top. This gives a look and feel that is similar to Windows' taskbar, and this is reinforced by the fact that this area also includes a clock.
The idea behind Webian Shell is that you can open a series of tab, each being home to a different web site or online service. Rather than having an email client running, you need simply open a Gmail tab. Instead of having Word running, you can just switch to your Google Docs tab.
The spread of online tools means that a program like Webian Shell is now viable. There is nothing to stop you from achieving much the same in your current web browser switched to full screen mode, but there is certainly no harm in trying a browser that has been specifically designed to run in this terminal mode. Built on Mozilla Chromeless, using this browser means you need not miss out on any web technology.