There are two levels of organization in your File, Photo, Address, Discuss and Bookmark applications. The top-level folders are called “Folder Sets” and the folders within Folder Set are just known as “Folders.” Paid accounts have 20 Folder Sets. Each Folder Set can contain up to 100 Folders with manila folder icons.
You can move folders from one Folder Set to another by using the “Customize” screen for the individual folder that you want to move. Follow the steps in the image below: