Old-fashioned media—books, tapes, CDs, etc.—are governed by the first-sale doctrine, a legal provision that allows a buyer to do whatever she wants with a copy.
The licensing of digital media, however, gives publishers far more power. Instead of selling an album outright, they can sell permission to access its contents for a fixed amount of time. (This is a boon for textbook publishers in particular. Under a digital regime, they may not have to worry about losing sales to students buying used copies.)
The licensing model stands to become the norm as physical media get phased out, says Mr. Hoek. “This isn’t just a music problem,” he says. Anything made of “ones and zeroes” can be kept on a leash.