as a replacement for Webscriptions. Existing customer's accounts and purchases were transferred to the new site. In December 2012, after making arrangements to sell Baen e-books at vendors such as Amazon.com, Baen increased prices and changed the way Monthly Bundles worked. Prices now depend on whether or not a book is also available in paperback format. Baen Monthly Bundles cannot be purchased after the middle of the preceding month, which is when hard-copy versions of the books usually reach retailers. Older Night Shade bundles are still for sale. Principles Baen Ebooks, like its predecessor, does not use DRM (i.e., copy protection), in accordance with Jim Baen's belief that DRM "just made it hard for people to read books, the worst mistake a publisher could make." Eric Flint, writing soon after Baen's death in 2006, noted that "in his fight against DRM, Jim stood alone as a publisher" and argued that Baen Book's success "demonstrated in practice that all the propaganda [in favor of] DRM is, in addition to everything else, so much hogwash even on the practical level of a publishing house's profits and losses." Jim Baen also believed in giving away e-book versions of older titles in order to sell newer titles, especially later titles in ongoing series. Because the cost of shipping e-books is essentially zero, it is cheaper for a publisher to give away entire books than to buy advertising, leading Baen to establish the Baen Free Library alongside Webscriptions. As Wired noted, the Free Library has "no conditions or strings attached ... not even requiring readers to give their e-mail addresses, which must have the marketing department turning green around the gills." Baen also include with some hardcovers CD-ROMs carrying dozens of the author's earlier books in multiple formats, all DRM-free. Charles N. Brown, whose Locus magazine tracked sales figures, noted in 2001 that "Baen has shown that putting up electronic versions of books doesn't cost you sales. It gains you a larger audience for all of your books. As a result, [Baen have] done quite well." Jim Baen also established a policy of making all Baen e-books free to the disabled. Baen Ebooks and digital identifiers The Digital object identifier (DOI) system would seem ideally suited to e-books, but Arnold Bailey found that Baen's approach to e-books made proper use of DOIs prohibitively expensive: Baen would have had to purchase a separate DOI for each