A shadow is not a copy an object. Instead, a shadow merely points to the original object. In effect, a shadow works with the original object, while a copy would work independently. Changes made to the shadow (for example, a title or icon change) will affect the original. The only exceptions are move and delete.

Shadows are useful because they allow you to practically store the same object in several folders. Since all shadows point to the original object, really it is the same object that is present in all those folders.

Note that even if you move the original object to a different location, a shadow will still point to the correct object.

There are several ways to create a shadow. See "Copy, move, and shadows overview" for details.