An estimated 1,500 book industry players gathered in New York on January 13–15 for the 2015 Digital Book World Conference and Expo, where talk about Amazon, e-book subscriptions, the growth of the Apple iBooks store, and the rise of self-publishing dominated the conversation. The conference was bookended by Amazon discussions—kicking off with an interview with Amazon senior v-p Russ Grandinetti and closing with a debate about whether Amazon should be constrained.

Interviewed by Michael Cader of Publishers’ Lunch and industry consultant Mike Shatzkin, Grandinetti was in peacemaking mode, in his most public appearance since Amazon’s bruising contract battle with Hachette Book Group concluded in November. But he made it clear that Amazon had no intention of backing down from its aggressive strategies. He said that “stability is hard to predict” when asked whether new contract terms would lead to a more stable marketplace for publishers, that “vocal, vibrant” author complaints only helped Amazon improve its services, and that he preferred Amazon Publishing to be measured “by its innovation.”

Grandinetti’s most interesting comments involved Amazon’s support for e-book subscriptions—a hot topic at this year’s show—with Grandinetti saying he was “cautiously optimistic” about the future of Kindle Unlimited six months after its launch. At a panel on e-book subscriptions, Nielsen BookScan’s Jonathan Stolper told attendees that e-book subscriptions represent about 5% of the book business—but that number jumps to 10% if Amazon Prime is included, which, though not truly an e-book subscription plan, does offer free e-books to customers.

On the panel, Kensington publisher Steven Zacharius and Simon & Schuster v-p Douglas Stambaugh, along with representatives from nascent e-book subscription providers Scribd and Oyster, heaped praise on the subscription model. “We make money on e-book subscriptions,” said Zacharius, with no discernible “cannibalization” of print sales. Stambaugh noted that “it’s early,” but that S&S is happy, citing a positive effect on the deep backlist, (echoing comments made by HarperCollins CEO Brian Murray at the 2014 Frankfurt Book Fair).

In other highlights, iBooks store director Keith Moerer said that the service is now attracting one million new users a week, thanks primarily to having iOS8 preinstalled on its phones and tablets. A closing panel looked at perhaps the most interesting facet of the digital publishing revolution—reader data. “The owners of e-book platforms now have unprecedented and previously unattainable knowledge about how people read,” noted the moderator, CCC’s Chris Kenneally. “They see every time an e-book is opened, on what device it is opened, how fast it is read, whether passages or entire works are reread, and perhaps most dismaying for authors, which books are never cracked, or never finished.”

The big question, Kenneally asked the panel, is how prepared publishers are to take advantage of such data. Bluefire’s Micah Bowers said the biggest adjustment may be cultural. “All the things publishers do can be highly informed by data,” Bowers said. “But in a lot of ways, it is not a matter of having the processes and job roles and the best practices and so forth, so much as it is counter to tradition and ego. There was a time where there was a magic to these decisions, a magic that data might take away. And that can create fear.”

Kobo’s Michael Tamblyn agreed. “There is apprehension institutionally because decisions can now be evaluated in a different way,” he said. But the way he sees things, digital reading data is a net positive. “Before, you had basically two ways to evaluate success,” Tamblyn noted. “There is the critical response, and unit sales. [Data] brings the reader into the picture.”

The event closed with an entertaining panel called “Should Amazon Be Constrained and Can They Be,” moderated by New Yorker writer Ken Auletta. The panel’s high point may have been when Barry Lynn, of the New America Foundation, described Amazon as a monopoly—a dominating company or cartel that can prevent competing products from going to market—which novelist and noted Amazon supporter Barry Eisler turned into a witty (and not inaccurate) description of the usual business practices of New York trade book publishers. So should Amazon be constrained? Yes, according to Lynn; no, according to Eisler; and maybe according to New York magazine writer Annie Lowie. Auletta, as moderator, claimed to be neutral, but a comment he made about Amazon, during his morning keynote speech, might be revealing: “If publishers don’t want Amazon to grow, they have to show they add value to the publishing process. Failure to do so will be suicide, not murder.”