I started developing TransparenTag File System to answer my personal problems with file organization:
The main idea behind TransparenTag is the following. Suppose, you have a beautiful photo of a sunset taken in New York. You can create a folder New York and a subfolder sunset and put that photo there. Later, you take a sunset photo in Moscow. You don't want to put it under New York/sunset so you end up with Moscow/sunset and two sunset photos in two different locations and can't easily browse all your sunset photos at once. Another option would be to make a top level folder sunset and put both New York and Moscow sunsets there but then you can't easily see all New York photos together.
By now, we all know the solution - you tag your pictures with New York, Moscow and sunset tags in your favorite application or website - be it Flickr, Picasa or something else. The only problem is that you can't easily move your tag database between these applications. There might be a tool to transfer tag data between Flick and Picasa but it can't support all possible desktop applications and websites.
This is where TransparenTag comes into picture. It makes New York/sunset and sunset/New York to show the same files, if you put something under Moscow/sunset, you can find it later under sunset/Moscow. Moreover, if I have time and strength to implement everything that I have in mind, you'll find all your sunset photos under sunset/+, with "+" subfolder automatically created under every folder to represent all files with given tags.
Of course, I have no control over photo sharing websites or applications that pay no attention to folder structure, but even this can change. One day, there might be an on-the-fly converter between your tracks' author and title properties and TransparenTag folder-tags.
You can say "Ok, sounds nice" but what if this TransparenTag goes nuts and I lose all my music and photos. Well, this can happen but TransparenTag was designed to minimize the risk of losing files and/or tags - it actually uses your regular file system to store all files, tags become a part of file names. A file sunset/Moscow/001.jpg is actually stored as 001-Moscow-sunset.jpg, so it is relatively easy to recover.