I respect the copyright of publisher and author, I also admire people sharing expensive knowledge to those who do not have the ability to get one.
This is a hard choice to me.
I actually bought more books by checking out the book first for free (often the sample part of an electronic book is not helpful) But I might not be representative.
The problem with allowing piracy will always be that no one really wants to spend money. Just because I have a spare $200 doesn't mean I want to spend it if I don't have to.
If you give people the choice between free and $x amount, 99% of people will choose free. You see this with just about anything that let's people name their own price.
