What do you mean, without DRM? Does Deezer provide you with mp3 files to put on your devices (ipod shuffle or similar)? Can you send a file to a friend? Or does Deezer forces you to be online and/or use Deezer's own app to listen to your music?

There are a lot of ways to engineer DRM in a system, I think you just don't see that you're actually using a DRMed system to play your music.