Droppy is a program that provides you with an alternative solution for switching windows when drag and dropping files or folders between screens. This type of application comes in handy especially if you're working with multiple or large monitors and it's difficult to transfer documents or folders from one window to another.
After you launch the utility, a new icon will show up in your Menu Bar. If you click it, you reveal the main window of the application. There, you can drag one file or folder at a time, configure the program's settings according to your needs, and check the About window.
The app lets you choose the dimension of the main screen and choose the proper window position on your desktop. Another good thing is that the program uses minimum CPU resources.
Personally, I'd prefer spending some cash and acquire a program that allows me to drag and drop multiple files or folders onto the app's main window. The fact that you can only transfer one document or directory separately might prove to be time consuming. On Mac App Store you can find various utilities that don't bring you this flaw and provide you with more useful features, like the ability to adjust the transparency level of the main window or define a global hotkey for revealing the program's screen.
With that being said, I'd suggest you try other applications.