David Streitfeld at the NYTimes on e-books keeping the conventions of their print ancestors:

Some functions of physical books that seem to have no digital place are nevertheless being retained. An author’s autograph on a cherished title looked as if it would become a relic. But Apple just applied for a patent to embed autographs in electronic titles. Publishers still commission covers for e-books even though their function — to catch the roving eye in a crowded store — no longer exists.

What makes all this activity particularly striking is what is not happening. Some features may be getting a second life online, but efforts to reimagine the core experience of the book have stumbled. Dozens of publishing start-ups tried harnessing social reading apps or multimedia, but few caught on.
Early television imitated radio when it first came out and the first automobiles imitated the conventions of horse carriages (the word ‘car’ is short for ‘carriage’).
Give it some time, e-books will find their voice too.