The problem with your computer's display is largely a problem of real estate, the fact that despite any 3D graphical magic happening on screen, your computer screen can't easily escape its two-dimensional boundaries.
Virtual desktops step in to maximize your screen's surface area by multiplying the number of desktop environments at your disposal and then organizing them so you don't lose track. Like Firefox and Internet Explorer's tabbed browsing, virtual desktop managers often organize your multiple display screens in tabs or slides that surface when you click.
Do you have a favorite virtual desktop manager? Share your pros and cons with us in the comments below.