I'm also trying to do so. Now there are at least two people want to place one file into multiple directories, which means store it actually once but you can see it in several directores. This will be good for some actual tasks. We do not need to care about keeping copys of one file in each directories synchorined.
Some people may get into several projects and have several roles. If someone want to see what document work they have done in the past year across all projects he engaged in, or just want to know how many creativities he has contributed to all projects, this will be hard in tradition file system.
If one file can be placed into multiple directories without storing multiple copys, the above problem will be easy.
In such a case, meeting_report.txt can be place at directories such as ActivitiesOf2009, Documents, Creativities, ProjectA, MaterialForBookTranscript. Thus, if the owner of these files want to know what he has down in the past year, he just need to go to the directory organised by time. If he want to finish writing his book he just need to go to directory specially organised for book writing. If he just need all the files for one on going project, entering the project directory is ok.
The function to store one file into multiple directories is useful. And of coure it can be done. We can place all the file into a database with multiple fields to describe the attributes of the files. Then we can develop a client which can make manage the file easy. Just as easy as windows explorer.
Whoever want to do so can contact me NewFileSystem@hcn.name, may be we can develop it together.
Or if you know that there is already such a tool, please notice me. Thank you!