12. The system of claim 9 wherein the storage and the classification module are part of an Internet-based storage service.
9. A file classification system, comprising: a storage; a classification module configured to, in response to a storage request for a file, extract textual content of the file, analyze the extracted textual content to determine a concept category to which the file can be assigned, assign corresponding tag information to the file, and save the file and tag information in the storage; and a user interface module configured to receive access requests from a first user that specify query tag information, to retrieve stored files from the storage that have been assigned tag information that corresponds to the query tag information by the classification module, and to present the first user with an option of (a) displaying a listing of the retrieved files, or (b) storing the retrieved files in a designated folder.