Had a long argument recently with a writer who was upset about how her books have been pirated as her sales have gone down. She went so far as to say that she thought every ebook should come with a virus that was only removed after you paid for it, a solution that would be at once disastrous and completely ineffective for its intended purpose.
For me, the question of piracy comes down to this: you can't stop piracy. You have a product that is infinitely reproducible at virtually zero cost. You can't fight that. And if you try, you're just going to end up frustrated and angry (like the writer I talked to).
So the problem really is: how can you take advantage of piracy, and how can you make money in spite of piracy? And those are the questions that need to be asked.