A truice in the battle between folders and tags.
File tree is the familiar and simple interface classic, the defending champion, the triumph of objective analogy.

It also provides the opportunity to create endless mess, that results in myriads of duplicated or lost files and labirynths of empty or outdated folders.
While structuring may involve metadata-like levels, there is no direct connection with metadata. And there is plenty of room for mistakes
The hipster runnerup, metadata is used for more precise, but thoughtful search.

The usual problems include: tons of unstructured results, human inability to acurately store index data of all files in their imperfect brains and the need to type.
Current ways to integrate search and tree systems unbearably stink of duckt tape.
Looking for a  photograph, that was shot in 2011 in RussiaMoscow.
This is an example of a treetag interface. It arranges tags into a comprehensive structure. This structure can be easily modified by dragging one of the layers up or down the ierarachy.

System comes with a big library of classes and tags. Still, user has the option of creating his own.

In the exampled interface there is a possibility to open a number of windows with different structures. Dragging a file to a window of a different structure will add the tags (and ask, if there are any conflicts). Saving a file to a location means tagging it too.
— So... I took a pic with that girl (what was her name?) in 2011 in... i think Moscow. Brings up Graphic, Year, Country and City by typing in “Photograph” “2011” “Russia” “Moscow” and selecting suggested layers.

— No, wait, was it Pskov? Goes up in city layer and opens Pskov folder. (he can also discard City layer to see all cities by dragging it to the search form)

— Ok, it’s not here. But it was in Pskov, i’m sure now. So it wasn’t 2011 then? Yeah, i should check May 2010.

Drags Year layer down (his current file selection is not affected). Goes to that layer and opens “2010”. Finds the damn picture.
— Thaat’s it. Mary. Name’s Mary. Adds a new tag to the file :-)
The principle can be applied in many instances that involve browsing, navigation or search.
Treetag can retain the sense of placement, reducing user's risk to get lost in the labyrinth of folders he created.
© 2011 Stasys Čhepulis