Adding to this, from going through their website, it's not as simple as "old" books are free and "new" books are a premium. I did a cursory look through their catalog and it looks like any book that is still selling well and under copyright has a price on top of the subscription fee. The DaVinci Code came out 12 years ago and is still $10 on top of a subscription, Storm Front (15 years old) is still $10 as well, A Game of Thrones (19 years old now) is $10 on top of a subscription fee, etc. Ten, twenty years is a relatively short period of time for a book to have existed, granted, but it's still a lot longer than the one year wait you'd get from Netflix.