It had to happen eventually: Amazon.com announced Thursday that it is selling more Kindle e-books than printed hardcover or paperback books.
Amazon said that since April 1, it has been selling 105 Kindle e-books for every 100 print books. Free Kindle books are excluded from that count; if free books were included, the number would be even higher.
Amazon CEO Jeff Bezos said the e-book threshold arrived sooner than expected. "Customers are now choosing Kindle books more often than print books," he said. "We had high hopes that this would happen eventually, but we never imagined it would happen this quickly." Amazon has sold printed books for 15 years and Kindle books for less than four.
Amazon doesn't share sales numbers but said it has sold more than three times as many Kindles books thus far in 2011 as it did in the same period in 2010.
The e-book surge is one of the biggest indicators of the impact of technology on culture, and the nation's public librarians have been careful observers of the trend for years. Many public libraries already offer e-book borrowing for free, subject to a library user loading special software on a desktop computer, mobile device or some e-book readers.
Amazon's news came as a surprise to Deborah Ervin, head of reference at the Framingham Public Library, a midsize library located in a Boston suburb.
"I'm certainly not opposed to [e-readers]," she said in an interview. "They are something people like and enjoy." Ervin likes using the Nook e-reader, sold by Barnes & Noble, which works with OverDrive software offered by her library and others in the Boston area's Minuteman Library Network for free e-book borrowing.
The convenience of replacing a heavy printed book, or several, with a lightweight e-reader is appealing, especially for somebody taking a long vacation, Ervin said.
"This is the latest and greatest technology, although many don't embrace it for one reason or another and might prefer holding an actual book, or feel e-readers are too complicated," she said. "Some people buck modern trends and would use a rotary phone if they could. Still, a lot of people use e-books almost exclusively."
While the Nook and Sony e-readers allow open e-book library borrowing, Ervin said she and other librarians are hopeful that Kindles will soon expand beyond letting users borrow only Kindle books from libraries. (In April, Amazon announced that it would allow Kindle book-borrowing from 11,000 U.S. libraries later this year.)
Ervin said users of e-readers tend to favor e-book buying rather than borrowing, since the purchasing process is relatively quick and easy.
"Borrowing an e-book is overwhelming sometimes, and the way OverDrive works is complex for some people to get onto their devices, whatever those might be," she said. First, you have to see what book is available, and then download the e-reader software and load the actual e-book onto the device, she said, adding, "It's cumbersome."
Ervin said she's not really misty-eyed for printed books and believes that soon enough, e-book borrowing will be much easier and more commonplace. For now, the inevitable replacement of print books with e-books continues unabated.
"In my own reference department, we have in the past ordered several titles of literary criticism in paper, but this year we stopped those and have them as e-books," she said. "That way, anybody can read them, even when the library is closed."
Matt Hamblen covers mobile and wireless, smartphones and other handhelds, and wireless networking for Computerworld. Follow Matt on Twitter at @matthamblen or subscribe to Matt's RSS feed. His e-mail address is mhamblen@computerworld.com.