A computer file format that stores multimedia playlists
MPEG-1 or MPEG-2 Audio Layer III, more commonly referred to as MP3, is a patented digital audio encoding format using a form of lossy data compression
|File nothing more||
"An m3u file is nothing more than a text file listing mp3 and or other format digital audio files to be interpreted by player software as a series of audio files to be played in succession"
from question "Is there an easy way to stream a m3u in iPhone?"