Amazon is taking steps to combat the deluge of 'spam books' uploaded to its Kindle store.

Kindle Direct Publishing (KDP) allows authors to upload books directly to Amazon's e-reader marketplace, which has shown itself to be both a boon for self-publishers and get-rich-quick schemes alike. The number of e-books available in the Kindle store has skyrocketed, but many are suspiciously -- or almost exactly -- similar in content.

Offered at very low sale prices (often $0.99 per book), the return to the 'author' is usually seen over time and in quantity. Many such schemes use "private label rights" manuscripts, which could be virtually copied verbatim and sold under a different name. Indeed, some of the books are even 'how-to' books on this scheme, with basic instructions and a copy of the manuscript to be 'written' (in most cases, paraphrased, in others simply re-formatted) and submitted to KDP.

However, some authors utilizing these practices began receiving letters from Amazon this week -- such as this one, posted in the "Warrior" Internet marketing forum:

"Certain of these books are either undifferentiated or barely differentiated from an existing title in the Kindle store. We remove such duplicate (or near duplicate) versions of the same book because they diminish the experience for customers. We notify you each time a book is removed, along with the specific book(s) and reason for removal...in addition to removing duplicate books from the Kindle store, please note that if you attempt to sell multiple copies or undifferentiated versions of the same book from your account, we may terminate your account."

While the practice of so-called "content spam" is threat enough to the self-publishing services, Amazon and the other e-book vendors with similar systems have noticed a corresponding increase in simple theft. Authors have seen unauthorized copies of their e-books -- sometimes identical, sometimes with altered titles and covers -- as well as unauthorized e-book versions of works published elsewhere (author blogs, literary websites, and the like are common fodder for the manuscript thieves).

Amazon's limited resources have before now seemed insufficient to identify or even halt much of this illicit traffic, and few self-publishing authors have the resources to wage an intellectual property lawsuit. The new campaign of letters may signal a renewed effort to spot and curtail the worst of these "undifferentiated versions", but more than one author has discovered that the originals are just as likely to be tagged as a copy.

James Lee Phillips is a Senior Writer & Research Analyst for IBG.com. With offices in Dallas, Las Vegas, and New York, & London, IBG is quickly becoming the leading expert in Internet Marketing, Local Search, SEO, Website Development and Reputation Management. More information can be found at www.ibg.com. Mark Sanders Tampa is a Tampa Florida fanatic! He is the leading authority on the geology and flora and fauna of Florida!