Slate, from a few years ago:

The fade-out—the technique of ending a song with a slow decrease in volume over its last few seconds—became common in the 1950s and ruled for three decades. Among the year-end top 10 songs for 1985, there’s not one cold ending.

Fadeouts are gone from popular music.

Advances in technology played a big part in the rise of the fade-out. Electrical recording emerged in the 1920s, allowing studio engineers to increase or decrease amplification. And achieving the effect became even easier when magnetic tape recording became widely available in the ’40s and ’50s. Many early fade-outs were added simply because engineers were short on time: To meet the demands of radio, or the limited runtime of one side of a vinyl single, they had to make the record fade out early.

And:

Done right, the fade-out is a song’s parting gift to the attentive listener. “Thanks for staying ’til the end,” it says. “Here’s a little somethin’ for ya.”

But what caused the fade-out to, well, fade out?

Let’s shift our accusatory fingers, then, to the iPod. That’s where our itchy thumbs have been stationed since Apple introduced the device in 2001. With a mere depression of the fast-forward button to get to the next tune, why wait out those last dwindling seconds?

This is a fascinating read. Especially the examples where little easter eggs are hidden in the lower volumes of the fade.

[H/T Brother Stu]