Amazon has begun to crack down on authors who upload copy-cat "private label rights" e-books via the Kindle Direct Publishing service. According to an e-mail sent to authors who had titles removed, Amazon will filter and delete "undifferentiated or barely differentiated" e-books submitted for publishing on the Kindle store, as they "diminish the experience for customers."

As pointed out by The New York Times, the Kindle store has been inundated with what are essentially duplicate e-books that were written and sold under "private label rights." The text of the book is sold by the original author or copyright owner for a flat fee, which authors or publishers can then ostensibly customize and sell under their own names. Unfortunately, few of the "authors" uploading these books do little more than format the text, create cover art, hit "upload," and hope for the money to start rolling in.

Furthermore, many of these so-called "private label rights" books are little more than an elaborate form of spam mixed with a sort of pyramid scheme. This is the way it works: you buy a $10 e-book that promises to tell you how to make a bunch of money publishing e-books via the Kindle store. Then the e-book explains how to obtain a copy of the text of the book to customize and republish as your own on the Kindle store. Then you sell the text of your book to the next person to "customize," on down the line.

Amazon has decided to become pro-active about limiting this sort of activity on the Kindle store to keep buyers from being overloaded with "duplicate (or near duplicate) versions of the same book." In addition to scanning for duplicate content among existing and new titles submitted for publishing, Amazon will also terminate accounts that repeatedly upload duplicate content.

Ironically, a user on the Internet marketing site Warrior Forum complained that a "Warrior Special Offer" to republish 22 private label books backfired when he received a notice from Kindle Direct Publishing that his titles were being removed.

"I had 22 books up, which only took a long weekend to 'write' (more like format) and publish," Warrior Forum user "brobdingnagian" wrote. "Of course anyone with more than half a brain (I stand disqualified, for obvious reasons) knows that you can't just take raw PLR and slap it into an ebook template and publish it."