We have heard that the medium is the message so many times that we have forgotten what it means, but consider the changes wrought in music's message as the media have changed. Could "Monster Mash" have swept the nation if the single were not the basic musical unit of its day? Would Marky Mark have ever gotten any attention if video hadn't killed the radio star? Desire only exists in mediation; the quality of fame is inextricably bound up in its channel of distribution.

Studio LP's posed few theoretical dilemmas; one had a certain amount of unreleased material, and a maximum length of 45 minutes per album. Start with the obvious hits at one end, start excising the duds at the other, and voila, you meet in the middle. So explicit was this lack of theory that albums which did take on larger theoretical problems were called "concept albums".

Greatest Hits compilations, the obvious forebears

to todays CD boxed sets, needed even less theorizing; start with the chart-topping hits and work your way down the Top 40. When you've got 40 minutes of music, quit.

The CD, however, despite being cheaper to produce per unit than LPs, has always been sold at premium prices. This meant that to attract new listeners, some difference besides mere fidelity had to be exploited in order to get people to switch from LPs to CDs. The obvious difference was length; a CD could hold half again as much music as an LP. Now no one was suggesting that artists were forced to abandon 20 minutes of good music every time they put an album out; on the contrary most albums obviously contained filler, so instead of selling more music, the CD marketers began selling more kinds of music - live cuts, extended dance remixes, rarities, whatever. By the time the LP had breathed its last, the customers had come to expect more music per disc.