Support for DRM in the recording industry is in freefall. On Tuesday, Napster released a new version of its music store offering 6 million DRM-free tracks.

Napster is a relative latecomer to this party, joining Apple , Amazon , and Wal-Mart , all of whom have had at least some DRM-free, major-label music available for about a year.

One difference, though, is that Napster is coming out of the chute with support from all four major...