In November 2013, Amazon launched Kindle MatchBook, a service that lets customers buy steeply discounted ebook versions of books they’ve already bought in print (from Amazon, of course) on Tuesday. Publishers must opt-in, and some already have with some 75,000 ebooks were available for $2.99 or less. Of course, it may prove difficult to persuade publishers to sell popular ebooks at such sharp discounts. NBC News’ Helen A.S. Popkin the selection “70,000 shades of blah,” pointing out the lack of bestsellers by authors such as Stephen King, E.L. James and Dan Brown along with classics by the likes of Mark Twain, Maya Angelou and others.