Tor kicked the expensive, unworkable DRM locks off their digital books just over a year ago:
For our particular readership, we felt it was an essential and fair move. The genre community is close-knit, with a huge on-line presence, and with publishers, authors and fans having closer communication than perhaps some other areas of publishing do. Having been in direct contact with our readers, we were aware of how frustrated many of them were by DRM. Our authors had also expressed concerns at the restrictions imposed by the copyright coding applied to their ebooks. When both authors and readers are talking from the same page, it makes sense for the publishers to sit up, listen and take note—and we did!
Have a read through to see what their customer and author responses were.