When browsing folders in the Finder, you may (or may not) have noticed that on the top of the folder in the Title Bar is a little icon next to the folder name. This is called a “Folder Proxy Icon” and enables you to easily move or copy a folder.
If you click on the icon, wait a moment until it darkens and then drag, you can move the folder even while its open to the Sidebar, to another folder, to the Desktop or even to the trash. If you wish to copy the folder instead of moving it, hold down the Option or Alt key as you drag.
Many applications contain a Folder Proxy icon in their open document windows as well. However, they may work a tad differently, depending on the application. For instance, if you drag the Folder Proxy icon from an open Pages document, it will create an alias of the document rather than move it whereas if you perform the same maneuver in a Microsoft Word 2011 document, it will move the document to its new location.