Amazon.com, the world's largest online retailer, blamed a computer "glitch" for stripping scores of gay-themed books of their sales ranking, preventing them from appearing on the site's best-seller lists. But a notorious Internet hacker is also claiming to be behind the mysterious happenings at the Web site, which is the top online bookseller.
Amazon would not elaborate on the cause of the glitch or why it seemed to mainly target books about gay and lesbians -- from academic treatises to romance novels. Some authors of the targeted books believe the company actively engaged in a discriminatory policy that hurt their sales.
The company did not respond to direct inquiries as to whether the Web site had been hacked, and blamed the disappeared rankings on a "cataloging error."
"This is an embarrassing and ham-fisted cataloging error for a company that prides itself on offering complete selection," Amazon spokeswoman Patty Smith wrote in an e-mail.
In recent weeks, a number of authors of gay- and lesbian-themed books noticed that the sales ranking -- a figure prominently displayed on the each book's sales page and the metric that determines how high a book will appear on lists of popular titles -- had disappeared.
When several authors contacted the bookseller to ascertain what happened, they say they were initially told their books had been branded "adult products," but similar books about straight sex retained their titles and appeared on popular title lists.
Craig Seymour said his book "All I Could Bare: My Life in the Gay Strip Clubs of Washington, DC," had lost its ranking while comparable books, including screenwriter Diablo Cody's stripper memoir "Candy Girl: A Year in the Life of an Unlikely Stripper," and porn star Ron Jeremy's autobiography "Ron Jeremy: The Hardest (Working) Man in Showbiz" retained them.
Rankings for books as diverse as Lisa Iannucci's "Ellen DeGeneres: A Biography" to Robert Aldrich's "Gay Life & Culture: A World History" were removed from the site.
Seymour said he spent weeks trying to get Amazon.com to explain why his book had lost its ranking and ceased to appear when the title or author was searched on the site.
"I did a reading in Chicago and people told me they couldn't find the book on Amazon," said Seymour, whose memoir was released late last year.
"I understand wanting to protect kids and keeping really explicit stuff off the main page," he said, "but when people searched by the title the book wouldn't come up. It's not really consumer centric if you can't find the book you're looking for."
After enlisting his publisher Simon & Schuster to intervene, the ranking on Seymour's book was restored.
Amazon said it was not just gay-themed books that were affected but "57,310 books in a number of broad categories such as Health, Mind & Body, Reproductive & Sexual Medicine and Erotica. This problem impacted books not just in the United States but globally. It affected not just sales rank but also had the effect of removing the books from Amazon's main product search," according to Smith's e-mail.
Until this incident, Amazon.com had successfully tread a line between being the go-to place for online family shopping and offering adults a wide variety of explicit material and sex toys.
Mark Probst, author of the gay-themed novel "Filly," said he received an e-mail from an Amazon member services employee, which he posted on his blog, that read: "In consideration of our entire customer base, we exclude 'adult' material from appearing in some searches and best seller lists. Since these lists are generated using sales ranks, adult materials must also be excluded from that feature."
The way in which a book becomes gets dubbed "inappropriate," however, is largely left to the site's users and is therefore susceptible to hacking, according to experts.
Though some authors saw their rankings disappear months ago, public outrage came to a boil over the weekend when Twitter users began alerting one another to missing ratings.
On Monday, just after outrage on the blogosphere reached a boil, a prominent hacker known as Weev claimed on his blog that he had harnessed the power of thousands of inadvertent computer users to flag books with gay descriptions as inappropriate, resulting in their sales rankings getting automatically removed.
On his blog, Weev wrote that by clicking the "report as inappropriate" button at the bottom of each page he was able to get rankings removed "with an insignificant number of votes."
First, he said he wrote a short code that would find books the site had tagged "gay" and "lesbian."
"From here, it was a matter of getting a lot of people to vote for the books," he blogged. Weev claimed he was helped by a friend at a high-traffic site who created an "invisible frame," which allowed users to inadvertently flag books when they were really visiting other unrelated sites. Weev said he "also hired third worlders [sic] to register accounts for me en masse" to target the site.
Weev's claims cannot be ignored, given his online prominence and a recent change to the Amazon Web site that removed the "report as inappropriate" feature. He was included in a New York Times Magazine article last year about "trolls," hackers whose primary goal is to make digital mischief on the Internet.
Weev's real identity was not revealed in the Times story and efforts to discover the person behind the blog were unsuccessful.
Without Amazon confirming if it was in fact hacked, it remains impossible to know for sure. But one computer security expert who examined the code Weev posted said it looked legit.
"It's extremely obvious that it should work," said Robert Graham, CEO of Errata Security, a consulting firm in Atlanta that works to protect computer systems.
"Cross site scripting in an endemic problem with Internet, and every major site is vulnerable, he said. "A post on one site causes something to happen on another site."
Weev, he said, was involved in 4chan, a group of anonymous hackers who "do this kind of thing."
By the end of the day Monday many books that had previously lost their rankings were showing them again, including works by James Baldwin and Gore Vidal.
"Many books have now been fixed and we're in the process of fixing the remainder as quickly as possible, and we intend to implement new measures to make this kind of accident less likely to occur in the future," Smith said in the e-mail.