From Hydrogenaudio Knowledgebase
After ripping and encoding a media file, many people choose to add tags to the file. These tags are a form of metadata designed to hold information such as artist, album, track title and so on. As different audio formats evolve so do different tagging specifications have been developed. Below is a brief summary of these tagging specifications. Also, each format has technical information.
To use the above tag formats you need some kind of tag editor. Most audio formats have their own program to add tags, but players like Winamp and foobar2000 can also edit tags and there are some general tagging utilities available (see the Download page).
Tagging standards have been set by the foobar2000 community, see here.
 Common Tags
There are many tagging standards, and many media players, with many interpretations. The following is an outline on the basics of tagging.
 Basic Tags
These tags are universal, and should work no matter what program or player you use. These are also the tags found in the ID3v1.1 spec. Note: The exact name of each field can vary from tagging standard to standard.
 Advanced Tags
These tags will get you less compatibility, but often times the basic tags aren't adequate for describing the media.
- ALBUM ARTIST
- and much more! (infinitely more)
 Personalized Tags
The use of these tags is sometimes frowned upon, because they don't really describe the media. Nevertheless, they have widespread use.
- ALBUM RATING
- FIRST PLAYED
- LAST PLAYED
- PLAY COUNT