This is a interesting feature of DropIt, because allow you to move your files in a destination directory, recreating the original folder structure.

You can for example drag&drop a folder like:
C:\Directory

To move files from:
C:\Directory\Subdirectory\File.txt

To a new destination like:
C:\Destination\Subdirectory\File.txt
or like:
C:\Destination\Directory\Subdirectory\File.txt

As you can see, DropIt has recreated a portion of the path of your files (\Subdirectory or \Directory\Subdirectory).

It works also with other actions like Copy, Compress, Extract and in general with all the actions that have a path as destination.

You only need to use %SubDir% and/or %DroppedDirName% abbreviations in your destinations. For example, to move the files as described above, you will use these respective destination folders:
C:\Destination\%SubDir%
C:\Destination\%DroppedDirName%\%SubDir%

Let's consider that I have a main Media folder that contains subfolders of music, movies and other stuff. I'm not very neat, so there are some subfolders that contain mp3, txt, doc, avi together.

Now I want to extract only mp3 files from there, but I want to keep the folder structure, because subfolders have names like U2, REM, Taylor Swift, etc.

What I need is to create a single association of DropIt, something like this:
Name: Move my music
Rules: *.mp3
Action: Move
Destination: C:\My Music\%SubDir%

And then drag&drop the Media folder on DropIt (yes, the folder that contains all my media files). The result will be something like this:
C:\My Music\REM\Everybody Hurts.mp3
C:\My Music\REM\Losing My Religion.mp3
C:\My Music\Taylor Swift\Love Story.mp3
C:\My Music\Taylor Swift\You Belong With Me.mp3
C:\My Music\U2\Beautiful Day.mp3
C:\My Music\U2\With or Without You.mp3

In bold you can see the folder structure recreated in this case by DropIt.

An additional tip: from DropIt Options you can select “Ignore unassociated files/folders”. It will help in this case, to ignore all other file formats during the process and do not have the popup message that asks if create new associations for them.