The fact that mp3's of dj sets are a good promotional tool can't be denied for sure but the other side of that coin is they have also decimated the mix cd business (that could also be seen as a good thing admitly) but up to maybe a year or slightly more ago mix cd's used to provide a handy income for the smaller labels with licensing money etc that just isn't there anymore as nearly everyone who is looking for a dj mix just downloads them now.