When the Compact Disc was being standardized, its capacity was set to accommodate the length of Beethoven's Ninth Symphony, reportedly at the insistence of Sony executive Norio Ohga. In retrospect it seems obvious that a media technology should adapt to media art wherever possible, not vice versa. This is less possible when new media technologies enable new forms of creation, but that's what makes them so exciting.
I've been working primarily on ebooks for the past 5 years, mostly because I'm excited at the new possibilities they enable. I'm impressed - and excited - when ebooks do things that can't be done for print books, partly because ebooks often can't capture the most innovative uses of ink on paper.
What Is Code?
Unfortunately, today's ebook technology standards can't fully accommodate this work. The compact disc of ebooks can store only four and a half movements of Beethoven's Ninth. That makes me sad.
You might ask, how does What Is Code? qualify as an ebook if it doesn't quite work on a kindle or your favorite ebook app? What Is Code? was conceived and developed as an HTML5 web application for Business Week magazine, not with the idea of making an ebook. Nonetheless, What Is Code? uses the forms and structures of traditional books. It has a title page. It has chapters, sections, footnotes and a table of contents which support a linear narrative. It has marginal notes, figures and asides.
Despite its bookishness, it's hard to imagine What Is Code? in print. Although the share buttons and video embeds are mostly adornments for the text, activity modules are core to the book's exposition. The book is about code, and by bringing code to life, the reader becomes immersed in the book's subject matter. There's a greeter robot that waves and seems to know the reader, showing the ebook's "intelligence". The "how do you type an "A" activity in section 2.1 is a script worth a thousand words and the "mousemove" activity in section 6.2 is a revelation even to an experienced programmer. If all that weren't enough, there's a random, active background that manages to soothe more than it distracts.
Even with its digital doodads, What Is Code? can be completely self contained and portable. To demonstrate this, I've packaged it up and archived it at Internet Archive; you can download with this link (21MB). Once you've downloaded it, unzip it and load the "index.html" file into a modern browser. Everything will work fine, even if you turn off your internet connection. What Is Code? will continue to work after Business Week disappears from the internet (or behind the most censorious firewall). 
I was curious how much of What is Code? could be captured in a standard EPUB ebook file. I first tried making a EPUB version 2 file with Calibre. The result was not a lame as I thought it would be, but stripped of interactivity, it seemed like a photocopy of a sticker book - the story's there, but the fun, not so much. Same with the Kindle version .
My experimentation with the code behind What Is Code? is another exciting aspect of making books into ebooks. Code and digital text can use a open licenses  that permit others to use, re-use and learn from What Is Code?. The entire project archive is hosted on GitHub and to date has been enhanced 671 times by 29 different contributors. There have been 187 forks (like mine) of the project. I think this collaborative creation process will be second nature to the ebook of the future.
There have been a number of proposals for portable HTML5 web archive formats for ebook technology moving forward. Among these are "5DOC" and W3C's "Portable Web Platform". As far as I can tell, these proposals aren't getting much traction or developer support. To succeed, the format has to be very lightweight and useful, or be supported by at least 2 of Amazon, Apple, and Google. I hope someone succeeds at this.
Best of 2015, don't you agree?
 In this case, the Apache License and the Creative Commons By-NC-ND License.