Rift is what's called a massively-multiplayer online role-playing game. And since MMORPG is too long, these games are usually referred to as 'MMOs'.
With an emphasis on the 'massive' part, these games are open worlds that encourage exploration, full of players from all over the globe either working together, fighting each other or encountering each other randomly.
Rift launched in early 2011 with an original soundtrack written by Inon Zur. And as for the size of the game, publisher/developer Trion Worlds recently nearly tripled the land mass available for exploration in Rift, thanks to an expansion called Storm Legion.
In such vast environments, music can be tricky. Sometimes, there isn't enough; sometimes it's too much repetition.
Inon was tasked with finding a balance, so he turned his attention to the players, reading online forums for feedback about the music in various locations in the Rift world.
He ended up writing almost as much music for the Storm Legion expansion as he did for the initial launch of Rift, but he wrote longer cues with more variations to prevent aural fatigue.
You can hear Inon talk about the new music for Rift: Storm Legion on the latest episode of Top Score from Classical MPR, also available on iTunes.