The Gnowsis DropBox is a folder where you can put your files and documents into. After a cofigurable amounth of time a popup appears proposing you a folder where the dropped document may belong to and some adequate tags. You also have the possibillity to add folders and/or tags by hand.

here is a sample screenshot:

http://gnowsis.opendfki.de/attachment/wiki/DropBox/DropBox.jpg