A vwm, or virtual window manager, is a tool that lets you have as much screen real estate as you want. Basically it gives you as many virtual desktops as you want, and lets you organize any open programs you have between them. Instead of just having one desktop with all your applications on it, you have several virtual desktops open at the same time, each with their own applications. You can only be seeing one of these desktops at any given time however. Usually there’s some kind of keyboard shortcut to move between them. Often there’s even a graphic representation of all the desktops and all the programs open on them. You can use this to both select different desktops and move applications between those desktops. To give an example, you can have a browser open in one window, all manner of chat programs open in another, and your mail client open in another, all without any clutter or confusion. In a way it simulates having a multi-monitor system, only not quite as convenient. Costs and space taken into consideration, having more than two monitors is only for the hardcore, but it's common to have four or more virtual windows under a vwm. While there's nothing built in to windows that lets you do this, there are many third party applications that add the functionality. Any decent shell replacement, like litestep or geOS will have some form of vwm.