The issue is basically ownership. For example, i have a shitload of records (yes, vinyl) that I don't have on CD. As far as I know, and someone needs to correct me if I'm wrong, there is no problem with me downloading an MP3 of, for example, a track from Pink Floyds "Umma-Gumma" or Depeche Mode's "A Broken Frame", since I own the records and just not the CD's. Also, if I have a CD, like my copy of New Order's "Substance" which is scratched on a particular track, I'm pretty sure that downloading that track is ok.