[Wolfstar]

Today, we are back to the style of selling music like it was throughout most of the 1950's--music sales by individual song.

Exactly, except sales by individual song goes back to Tin Pan Alley days and the popularity of sheet music. The emphasis on selling only albums is a comparatively recent development.

[RayChuang88]

I think what made the album possible was the development of the LP in 1948, which allow 14 minutes per side on a 10" disc and 23 minutes per side on ad 12" disc. Essentially, the 12" LP won out, and that led to the 8-12 song album for popular music being the standard format by the early 1960's.

Today, with digital downloads, we're going back to the single-song sale format, unless people want longer play from a single release. We may see singles being longer than before, too.