The E is for Enhanced
How do you make someone buy a book they probably already own, and can get for free either legally or illegally? You enhance it:
The first title in [the Penguin Enhanced e-Book Classics series], Pride and Prejudice, will debut this summer and include such bells and whistles as reviews (of the original publication), a filmography, recipes and notes on etiquette. Nine more titles will be released as Enhanced e-Book Classics throughout the fall.
(From Publishers Weekly, which also notes Penguin’s e-book sales spike)