I'm looking for the best approach to manage uploaded files by subject area. I would like to have the ability for users to upload and share files on a set of predefined subjects. For example one user uploads a Word document on a subject X where she would identify the subject area when doing the upload. Another user a pdf file on subject Y. We would like a way for users to access a page which would be "library" of the uploaded files catagorized by subject. All users would have access to all subjects. Securuty is not an issue.