DirectSong

DirectSong is a premium music service that sells extra audio content for Guild Wars. When DirectSong music is playing in the game, the Direct Song icon in the Options panel will light up.

Their current wares (for Guild Wars) are:
 * Guild Wars Special Edition Soundtrack
 * Guild Wars: Special Edition Bonus Music (free) - 4 additional tracks
 * Battle Pak 1
 * Sorrow's Furnace Mini-Pak (free)
 * Guild Wars Factions Soundtrack
 * Guild Wars Factions Collector's Edition Expansion Music (free)
 * Guild Wars Nightfall Collector's Edition Bonus Music (free)
 * Guild Wars Nightfall Soundtrack

When the Sorrow's Furnace update came out, the associated music was only available via DirectSong, though it was offered for free.

DirectSong's music is only available as protected (through DRM) WMA files with a bitrate of 128KB/s for the original Guild Wars, and 320KB/s for Guild Wars Factions.