A toolbar is simply a linear collection of shortcuts to files, folders, and programs that appears somewhere on your desktop. Sometimes the toolbar appears on the sides or top of the screen, sometimes it is made to disappear when not being accessed, and sometimes it can have special effects and animation to give your computer interface a touch of pizzazz. In my book, I explain that toolbars should only be used to store shortcuts to frequently used programs and folders. This helps relieve the need to place shortcuts on the Desktop, or navigate through the Start menu to find programs listed there.
By using toolbars, you can speed up access to your popular programs and folders while at the same time taking up no additional screen space for icons (by hiding the toolbars when not in use). Toolbars, like the Desktop, are a great asset in organizing the contents of your computer to be able to access them quickly and easily. I also recommend checking out the StarDock ObjectDock if you like the OS X toolbar look and feel, but use a Windows operating system.