Named data streams allow applications to attach information to a file that appears to be hidden. An administrative program could use this to attach file usage information, backup information, and so on. An application could use this feature to hide or collect file attachments. For example, a multi-media document could have all text, audio clips, and video clips organized in one file rather than in several files. A document being reviewed by multiple people could have each person's comments attached to the file as a named data stream.