A judge has ruled that users do not have the right or ability to resell songs purchased through iTunes as one might do with used CDs or DVDs. This is one of the on-going arguments that relate to digital media and ownership. Much like software, it would appear that users are granted a license, rather than an owned copy, to use a song.
This ruling comes about from a lawsuit between ReDigi and Universal Music Group's Capitol Records. Universal sued the start-up saying that the company was violating the former's copyrights by enabling users to resell purchased iTunes music.
U.S. District Judge Richard Sullivan's ruling says that (paraphrased) without explicit permission from a copyright holder, you are not allowed to resell a digital media file. The full decision is available US' Archive site.