Shuffling, semantics and desires

A while back I ran into this piece by Steven Levy: Does Your iPod Play Favorites? I planned on a writing post about it, but I forgot until today.

The article addresses the fact that when the iPod Shuffle randomizes a playlist, it's frequently the case for a shuffled playlist to include three songs in a row by the same artist. Apple's engineers and a Temple university professor assure Levy the iPod is shuffling just fine--the resulting playlist is indeed random--but what's not addressed in the article is that as far as the shuffling goes, semantics aside, there's still a gap between a randomly shuffled playlist and what is actually desired.

When we say we want our songs shuffled, what we want is not merely a random shuffling in a mathematical or algorithmic sense, and assurances that the playlist is randomly shuffled do little to solve the problem. What we want is more restrictive. Like Levy, we want a shuffled playlist the doesn't contain multiple tracks in a row from the same artist (or possibly the same disc). Given the presence of artist and album information and a sufficiently diverse playlist, it shouldn't be hard to enforce this additional constraint on the resulting playlist.