An interesting post.

• First, most people buying and reading ebooks are not reading them on dedicated readers; there are more people reading ebooks on iPhones than on Kindles. I'd worry less about the devices, than I worry about the increasing restrictions on copyright and international import/export of books in digital form. Access is a much bigger problem than platform. Copyright is being abused to prevent sales in new countries.
• Second, DRM or Digital Rights Management is stupid, and doesn't work. I'm sorry to see that Apple has caved in and is allowing DRM on their iBooks -- but implementing the DRM is going to be up to publishers, which is something. DRM does nothing to stop pirates, but frustrates honest readers, all the time.
• Third, there's are a lot of free and un-DRM ebooks available now, but I don't know how long that will last. In terms of serendipity, it's worth looking at the data on how people purchase ebooks; there's a lot of "if you like X, you might like Y," built into the books, and the sites selling the books. They work. You'll increasingly see this built into the metadata used by libraries, too, as the data is provided by publishers— interestingly, they seem quite willing to recommend books they don't publish, because they realized other publishers are doing the same thing.
• Fourth, I made my first professional ebook in 1989, and it's still available today, but mostly, because I keep producing new versions of the file. Ebooks, in order to actually be affordable and practical need to be device neutral. We're right now at the point the record industry was in in the first half of the twentieth century when RCA vinyl records would only play on RCA turntables, Victor on Victor turntables, etc. We need to have open standards, and publishers need to agree to them. So far, every time an open, DRMless standard is created, publishers mess with it.
• Fifth ebooks are not archivable in terms of the standards of professional archivists. The file formats change, they are tied to hardware, they are stored on non-reliable media. This too relates to standards.
• Sixth I am positive ebooks are not going to reach even 50% of sales for consumer books, fiction or non fiction, for at least fifty years. You can't lend them, legally. They are device dependent, they are potentially dangerous in terms of malware, they are tied to specific countries of origin in terms of access (UK Kindle owners can't buy US Kindle books; they have to wait). The printed codex book requires no external power, is portable, is completely debugged in terms of UI and basic operating, is archivable (a modern paperback printed on low-acid recycled paper, as is increasingly the consumer mass market standard because it's cheaper, is much better in terms of lifetime of use than a current ebook).
• Seventh The current discussions about ebooks, the digital divide, and readability have not changed since the 1990s.