According to forbes.com Tim O’Reilly has said:
We’re delighted when people who can’t afford our books don’t pay us for them, if they go out and do something useful with that information.
Let’s say my goal is to sell 10,000 copies of something. And let’s say that if by putting DRM in it I sell 10,000 copies and I make my money, and if by having no DRM 100,000 copies go into circulation and I still sell 10,000 copies. Which of those is the better outcome? I think having 100,000 in circulation and selling 10,000 is way better than having just the 10,000 that are paid for and nobody else benefits.