The SF author Jeffrey Carver has come to the conclusion that offering his backlist as free ebooks just isn't working for him.
I've been running the free-downloads experiment for more than two years now. Here's my conclusion: The free downloads have significantly expanded my audience, and enabled me to meet some very nice people electronically. But they haven't done much in terms of pay. Yes, some people have been generous with Paypal donations, and some who liked the books have gone out and bought my other ebooks—and I thank you all from the bottom of my heart. But the theory that free downloads drive sales of books, which apparently works for some writers, does not seem to have clicked for me. I don't regret offering the downloads—not a bit—but now it's time to try something new.
This same model appears to work for Baen Books, so I wonder why it's not working for Jeffrey?
Actually, let me rephrase that sentence. We know this model worked at one time for Baen Books, but we don't know that it's working _now_. Market behavior might have shifted in the 8+ years since Baen first started giving away ebooks. This model might not be working for them anymore, either.
On the other hand, Baen saw an increase in paper books, and Jeffery didn't mention them in his post. Perhaps that is the difference.