As someone who already thinks $79 is a relatively low price to pay for unlimited two-day shipping from Amazon, where I buy an obscene number of products, much less for that shipping plus streaming from a decent-sized video library. So the news that Amazon is exploring doing some sort of “Netflix for books” option seems like a suspiciously good value for the money. Tim Carmody, in a typically thoughtful post, explains why the pricing part of it is in fact the biggest challenge both Amazon and book publishers, and why it probably means that the plan will work more like Netflix’s discs-per-month program than its unlimited streaming program. The program will need to be profitable enough for publishers to digitize their back catalogues, and Amazon will probably want to calculate the point at which high-volume users will keep pulling the trigger and still buying additional books but below which new users won’t buy e-readers and pay their $79 annual entry fee. Seems pretty reasonable to me. I’ve already punched my ticket to Prime and am buying books like a maniac. And they’d really clean up if they found a way to translate comic books and magazines for e-readers, maybe by making the Kindle app full-color even if the device itself isn’t.