In trying to nurture Amazon’s service, the four major record companies have offered it one potential edge. One by one, they have agreed to offer their music catalogs for sale on the service in the MP3 format, without the digital locks that restrict users from making copies of the songs. (Sony BMG Music Entertainment, the second-biggest company and the last holdout, signed on last week. Sony BMG is a joint venture of Sony and Bertelsmann).

— Music Industry, Souring on Apple, Embraces Amazon Service - New York Times