U.S. District Judge Richard Sullivan issued a judgement on Monday that effectively says that customers can not re-sell digital music files. In other words, unlike a CD, which customers do have a legal right to re-sell, once you've bought a song via download services like iTunes, it's yours.
The case involved Universal Music Group’s Capitol Records, which sued ReDigi, a company offering to sell your digital music when you no longer wanted it. AllThingsD reported that Judge Sullivan granted a partial summary judgement in Capitol Records's favor, though both parties will find out the next step in the process on April 12th.
A brief look at the ruling shows that one of the most important factors the judge based his opinion on is the right to control reproductions granted under copyright. Though ReDigi claimed that it wasn't copying the music file to its servers when it...err...copied the music filed to it servers, the judge found that this simply isn't the case.
By copying that file, and then later allowing it to be downloaded by another customer, copying takes place in violation of copyright protections.