Cory Doctorow has been saying for a couple of years that giving away his books online has helped him sell more. I agree but I always thought that he was using that as fact in debates where really, it’s just an opinion. Not that there’s any way to get actual numbers so he’s not cheating, it’s just his use of that opinion I found a bit dishonest. In this article at Forbes mag he gives a bit more of a statistical answer that helps me accept his (and mine) gut feeling a bit more:
There’s no empirical way to prove that giving away books sells more books—but I’ve done this with three novels and a short story collection (and I’ll be doing it with two more novels and another collection in the next year), and my books have consistently outperformed my publisher’s expectations. Comparing their sales to the numbers provided by colleagues suggests that they perform somewhat better than other books from similar writers at similar stages in their careers. But short of going back in time and re-releasing the same books under the same circumstances without the free e-book program, there’s no way to be sure.
He also ends with the actual no question proof that sharing his work helps; it helps his brand and just that is worth the few sales he might have lost:
It’s good business for me, too. This “market research” of giving away e-books sells printed books. What’s more, having my books more widely read opens many other opportunities for me to earn a living from activities around my writing, such as the Fulbright Chair I got at USC this year, this high-paying article in Forbes, speaking engagements and other opportunities to teach, write and license my work for translation and adaptation. My fans’ tireless evangelism for my work doesn’t just sell books—it sells me… The Internet not only sells more books for me, it also gives me more opportunities to earn my keep through writing-related activities.
Same thing with blogs, and more generally with webtwenny type things like APIs, have confidence in your “stuff” and share it, have confidence that the goodwill / visibility / reputation it brings will be worth more than what you might “lose”.