This is one of Microsoft’s hidden gems in my honest opinion and a great app for synchronising multiple folders up for backup or just syncing various PCs up with same files and data,
There are files from all kinds of sources that we want to store and manage. Files are created by our digital cameras, e-mail, cell phones, portable media players, camcorders, PDAs, and laptops. Increasingly, computer users are using different folders, drives, and even different computers (such as a laptop and a desktop) to store, manage, retrieve and view files. Yet managing hundreds or thousands of files is still largely a manual operation. In some cases it is necessary to regularly get copies of files from another location to add to primary location; in other cases there is a need to keep two storage locations exactly in sync. Some users manage files manually, dragging and dropping from one place to another and keeping track of whether the locations are synchronized in their heads. Other users may use two or more applications to provide this functionality.