Tagging your media files means putting some type of metadata (information about the data) inside of the data itself. For instance, your mp3 or ogg song can have information about the artist, title, genre, etc. stored inside the file itself. Now this only really helps you if you use applications which read this information out of the file, but most modern applications do. This will become very important as we switch to filesystem and application combinations where it becomes less obvious where your files are stored on your disk. Some examples of the the concept are GMail's searching for messages instead of organizing them in folders, or some of the desktop search tools like Mac OSX's search tool, or the open source Beagle project. None of these systems will work without good metatdata.. and the most useful form of metadata for binary files, like pictures, music, and movies, is a specialized internal tag.

We're only going to cover tagging a few types of files today because, frankly, these are the only types of files that I use often. We'll cover tagging MP3 and OGG music files and JPEG images.