One feature that Unix-based operating systems have had for years (but Windows hasn’t) is virtual desktops. When you boot up most flavors of Linux, for example, you’ll see an odd feature on the taskbar: a grid, usually with four “buttons” on it. These four buttons represent four virtual desktops. You just click on a button to switch to a different desktop; you can even move windows back and forth between the virtual desktops.
Why would you want a feature like this? Because it allows you to organize your desktops in any way you see fit. Perhaps you’d like one desktop with all of your web applications (web browser, email client, etc.) and another desktop with all your local applications (Word, Excel, etc.). Perhaps you’re working on a couple of projects at once; you can use one desktop for all the windows for one project, another desktop for another project, and another one for your email and web browsing. Or maybe you just want to be lazy at work: virtual desktops mean that you can have one desktop with a browser open to an online poker site, and another desktop open with some Excel documents, so it looks like you’re working. That way, if the boss comes around you can look productive with a single mouse click!