Spam has hit the Kindle, clogging the online bookstore of the top-selling eReader with material that is far from being book worthy and threatening to undermine Amazon.com Inc’s publishing foray.

Thousands of digital books, called ebooks, are being published through Amazon’s self-publishing system each month. Many are not written in the traditional sense.

Instead, they are built using something known as Private Label Rights, or PLR content, which is information that can be bought very cheaply online then reformatted into a digital book.

via Spam clogging Amazon’s Kindle self-publishing | Reuters.