How to Buy and Sell the Digital Movie Codes that Come With Your Discs

At the moment, we’re in a transition to an all-digital world of entertainment, and we’ll soon be able to more or less forget about DVDs, CDs, Blu-rays, and game cartridges. But while we sit in this transitory phase, movie studios are trying to get us to keep buying movies on disc by sweetening the pot with free codes for digital copies.
by Michael Crider via How-To Geek