Mp3 is an abbreviation of  "MPEG Layer 3 file".  An mp3 file is an audio file that is much smaller than other formats.  The reduction in size is achieved by removing frequencies that can't be heard by the human ear.  The main advantage of an mp3 file is that it takes up less space than other formats.

An mp3 file can be tagged with identifying information using ID3 tags.  ID3 tags are used by databases such as iTunes to classify mp3 and mp4 files.  ID3 tags were invented by Eric Kemp in 1996.  ID3 is an abbreviation of "IDentify an mp3".

The following information can be attached to an mp3 file using ID3 tags:

• Title
• Artist
• Album
• Year
• Genre

Mp3 files made by Audio Transfers have ID3 tags.