A study presented by book marketing firm Verso Advertising at Digital Book World last week finds that 15.8 percent of book buyers already own an e-reader — that figure has doubled since 2010. But 51.8 percent of book buyers say they are “not at all likely” to purchase one in the next 12 months. That is up from 40 percent in 2009. Update: Here’s our follow-up post on why some book buyers are increasingly resistant to e-readers.

Among “avid” book buyers — those who purchase 10 or more books per year — e-reader penetration is more pronounced: 22.3 percent of avid book buyers already own an e-reader, and 10.1 percent say they’re “very likely” to buy one in the next 12 months. But 49.7 percent of avid book buyers say they are not at all likely to purchase one.

Tablet usage shows “accelerated early majority” phasing: 15.2 percent of book buyers own a tablet and 9 percent are “very likely” to buy one in the next 12 months.

Verso predicts an installed base of e-readers and tablets in the 25 to 30 percent range in the next year — with the resistors staying even at about 50 percent of the population.

Verso’s findings dovetail with some research from Bowker/BISG that found e-book growth slower than previously predicted. When Bowker asked e-book power buyers (who buy at least four e-books per month) what is keeping them from buying more, 28 percent said “cost”, 27 percent said “nothing” and 25 percent said they didn’t have enough time. Those factors may affect e-reader resistance, as well. Update: Here are some more reasons.

Verso’s study was conducted between November 30 and December 4, 2011 and had 2,200 respondents. More here.

See all our Digital Book World coverage here.

Grandinetti said “we’re trying to be skeptical about this” but Amazon’s early data “suggests you can get people engaged in a book that they weren’t interested in otherwise.” Amazon compared two customer groups of Amazon Prime members who have owned an e-reading device for more than six months and have made at least one recent book purchase in the last 30 days. The members of one group used the Kindle Owners’ Lending Library and the members of the other group did not. Grandinetti said that after after the average customer’s first borrow from the KOLL, he or she went on to purchase 30 percent more books.

“Many publishers in this room give away books for free every day in a very coarse effort to increase demand,” Grandinetti said. He argued that the Kindle Owners’ Lending Library is a more refined approach backed by a lot of promotion on the Amazon website. “Some customers may be willing to try authors and series they might not otherwise have discovered,” he said. He gave an example, the very popular Hunger Games trilogy by Suzanne Collins. Nineteen percent of customers who borrowed The Hunger Games from the KOLL later purchased one of the other books in the trilogy instead of waiting another thirty days to borrow it.

The Hunger Games books appear to be among those included in the Kindle Owners’ Lending Library without explicit publisher permission. Instead, Amazon is paying the publisher the wholesale price for the book each time a customer borrows it. This is different from KDP Select, which allows self-published authors to include their books in the KIndle Owner’s Lending Library if they agree to sell them exclusively through Amazon. (Some KDP Select authors have found that this exclusivity pays, while others are skeptical.)

Amazon clearly hopes to convince traditional publishers that it is worth their while to agree to include their e-books in the KOLL, as well as to decrease skepticism about the program. It was unclear if publishers were convinced. Later in the day, Publishers Marketplace’s Michael Cader asked publishers if it’s true that the Kindle Owners Lending Library increases sales. “Are you just netting more revenue because you’re getting paid by Amazon for the read?” he said, referring to the cases in which Amazon pays the wholesale price each time the book is borrowed, rather than coming to any other kind of agreement with the publisher.

Bloomsbury’s Evan Schnittman pointed out that Bloomsbury runs similar promotions already. For an upcoming children’s series, for example, Bloomsbury released three free prequels leading up to the launch of the first book in the series. He pointed out that Grandinetti’s Hunger Games example was also about a series and it was unclear how giveaways affect paid sales of single books, especially if the author in question has not published any other titles that might enjoy a resulting sales bump. Also, as Cader noted, when publishers run the giveaways themselves they can control the timing and the length of the promotions.

Grandinetti stressed the data is “early.” “I don’t want anyone to think we’re definitive on this,” he said, “but this is the actual data on this and we’re doing our best to really map this out.”

The Digital Book World conference took place in New York this week. See all our Digital Book World coverage here.

Publishers see both opportunities and challenges as they enter the world of e-singles. In general, e-singles are shorter than full-length books, published in relatively short timespans and exclusively in digital formats (at least at first). After that, the similarities end — Random House is publishing four original nonfiction e-singles in partnership with Politico, for instance, while Hachette’s sci-fi/fantasy imprint Orbit is publishing short fiction. The Atavist publishes nonfiction e-singles, and Penguin is releasing a mix of fiction and nonfiction under its three-year-old “e-specials” program.

Random House’s Jon Meacham advocated publishing partnerships, as RH has with Politico: “There’s a reason journalism faces extraordinary financial challenges, and you don’t want to just replicate that,” he said. He explained why a partnership works: It “increases the discoverability and the prominence both of Random House and of Politico” and has a built-in audience, Politico’s readers.

“We’re trying to replicate journalism’s extraordinary challenges in an entirely new place,” Ratliff joked. The Atavist plans to launch a yearly subscription model, “bringing a magazine element into what are essentially books” and letting subscribers receive one original e-single a month.

The panel’s moderator, Jack Perry, asked how publishers should market e-singles. Penguin wants to publish e-singles that “fill a genuine gap in the market,” said Carrie Swetonic, associate director of marketing at Penguin’s Dutton imprint. While Orbit indicates that its e-singles are not full-length books by putting an “Orbit Short Fiction” sticker on the cover, Penguin “doesn’t do much to advertise” the length. The main indicator of shorter length is that the e-singles are priced low, between $2.99 and $5.99. “Length is not the driving factor for people who are buying these,” said Swetonic. So far Penguin’s strategy is working at least for some titles; Swetonic said the company is happy when an e-single sells “tens of thousands of copies.”

“The content has to be really good and the bar’s even higher in these early days,” said Meacham. “We have only so many shots at readers. If [publishers] think this is just a way of getting anything written out there, as opposed to something that’s been edited and watered and fed and cared for, we risk screwing up the genre on the front end.”

“Is this actually a genre at all?” wondered Ratliff. “We’re untethered from the print world.” He doesn’t think e-singles need to be cordoned off as a category of their own. “It’s whatever length that makes sense for whatever kind of story you’re telling.”

One question went unanswered — What kind of returns are traditional publishers expecting from e-singles? Will they contribute to the bottom line any time soon or do publishers see them as a relatively inexpensive way to experiment? It was unclear how the programs at Penguin, Random House and Hachette fit into broader company initiatives and digital revenue goals, and that’s a question I hope to explore soon.

The Digital Book World conference is taking place in New York this week. See all our Digital Book World coverage here.

“It’s a myth that individuals who buy e-readers or buy tablets suddenly stop buying print books all together,” said Hilt. He said B&N data shows that the first three months after a consumer purchases an e-reader, it’s a novelty “like any new device or toy. They experiment and buy a lot of content.” Then, he said, “You realize, ‘You know what? I still love to go to Barnes & Noble.’” (Or the book section of Target or the library, he added.)

With the e-reader honeymoon over, Hilt said, power buyers (those who buy four or more titles per month) go back to purchasing a “stabilized mix” of e-books and print books and books borrowed from the library. That contradicts research presented by Bowker in the previous panel, that seven to twelve months after buying their first e-book, 72 percent of power buyers switch over to e-books exclusively.

Hilt seemed to encourage the practice of browsing in bookstores and then buying anywhere, but he did not explicitly address how Barnes & Noble can discourage readers from browsing in B&N stores and then buying on Amazon (NSDQ: AMZN) (nor did he acknowledge that that is a problem). He did say that Barnes & Noble is “not competing with the independent [bookstores]” and that the company might be willing to share data about book buyer behavior with the indies — though he did not explain how that process would work or whether Barnes & Noble is ready to start sharing the data anytime soon.

The Digital Book World conference is taking place in New York this week. See all our Digital Book World coverage here.

To be sure, this growth varied by genre, noted Bowker’s Kelly Gallagher at Digital Book World this morning. (Bowker conducted this research with the Book Industry Study Group.) E-books now make up 26 percent of adult fiction purchases, compared to 11 percent of children’s book purchases and 3 percent of cookbook purchases.

Seventy-four percent of book buyers have never bought an e-book (and 14 percent of those actually own an e-reader or tablet but choose not to use it to read e-books).

Bowker looked at the habits of “power buyers” — people who purchase four or more print or e-books per month. “Whether print or digital, publishers’ best customers now look alike,” said Gallagher.

Print power buyers make up 22 percent of the overall print book-buying population, and they drive 53 percent of print book purchases overall.

Meanwhile, e-book power buyers make up 35 percent of the overall e-book buying population, but they drive 60 percent of overall e-book purchases. In other words, about a third of the overall buyers drive two-thirds of overall purchases. Casual e-book buyers “are not pulling their weight” compared with casual print book buyers, Gallagher said.

There’s a bright spot for e-book growth: Around 7 to 12 months after buying their first e-book, 72 percent of power buyers switch over to e-books exclusively.

Overall, though, print power buyers slowed their entry into the e-book marketplace in 2011. “That’s why we didn’t see exponential growth,” Gallagher said. And beyond those power-buying voracious readers, casual e-reading is at risk: As more people buy tablets, e-reading becomes just one option among many.

The Digital Book World conference is taking place in New York this week. See all our Digital Book World coverage here.

The Sesame Street e-bookstore contains 160 e-books, many of which are also available as print books. The target audience is 2- to 6-year-olds. The company has also published 40 standalone e-books and 25 paid and free iOS apps, 13 of which are based on existing print books. Those book-based apps account for 52 percent of unit sales for all Sesame Street iOS apps.

All of the apps are English-language, and they’ve been purchased by customers in over 75 countries. This year, Sesame Workshop aims to translate its English apps and create localized content — which can be challenging because Sesame Street characters are different around the world.

Sesame Workshop’s Jennifer Perry shared the company’s best practices for reaching preschoolers on digital platforms at Publishers Launch Conferences’ “Children’s Publishing Goes Digital” this afternoon. Here are a few highlights of what the company has learned from the research it conducts in partnership with the CUNY Center.

Usability (Or, Design For Small Hands)

»  Easy access to all key features at all times is essential. Individual pages, activities, parent tips, settings, etc. should never be more than one or two taps away, via an on-screen menu or index.
»  Make it easy to turn off extras (like narration, parent tips and music) and skip introductions and instructions after the first use. “Parents don’t want to sit through it again, and neither does a four-year-old,” Perry said.
»  Research shows that preschoolers don’t understand instructions if they’re simply told, so audio prompts should be accompanied by visual enhancements (an arrow with a “turn the page” prompt, for instance).
»  Preschoolers have a hard time holding iPhones and iPads vertically, so design in a landscape mode. Position icons away from the bottom of the screen, where a preschooler is resting his or her wrists.

Comprehension: “Errorless Learning”

»  Provide a demo, especially for parents, so they’re aware of all the app’s features as they’re using it with their kid.
»  Relate any game or enhancement directly to the storyline. Parents “respond negatively” when enhancements are thrown in just as extras.
»  Repeat hints, especially on story pages where a kid might be distracted by a storyline. Add a “subtle glow” around a hot spot, for instance.
»  The app shouldn’t linger on one activity indefinitely. Move to another “round” after three to five gameplays. “Five rounds of a game is the maximum that a child finds engaging,” Perry said, “and definitely the max for parents.”
»  Provide audio or visual rewards for completion of activities.

Add-Ons for Parents:

»  Sesame has found that parents are open to cross-sells and promotions within an app, but don’t want their child to run across them. Promotional stuff should go in the “Parents’ Tips” or “About” section of the app.
»  Parents like “extension activities” — related projects they can do with their kids outside the app.

And a few ongoing questions — Sesame is still researching the answers to these:
»  Which platforms will become the most commonly used for preschoolers?
»  How do parent-child interactions differ when reading a print book versus reading an e-book?
»  Which design features prompt more parent-child interaction?
»  Which designs hold children’s attention best? Which designs and platforms best improve comprehension?

Children’s Publishing Goes Digital is a special session at the Digital Book World conference, which is taking place in New York this week. See all our Digital Book World coverage here.