title_body: What triggers the "adult" designation on Amazon Kindle books (romance genre)? I do software development for an ebook publisher specializing in Romance novels. One thing we encounter from time to time is that a book gets classified by Amazon as "adult". That effectively removes the book from normal searches. We can't figure out what triggers the "red flag" and Amazon isn't saying. The cover art doesn't seem to be any better, worse, more suggestive, whatever. Covers are definitely tamer than directly competitive books. Nothing stands out for us in the book content. It's a case of "If A, B, and C are fine, why did D get flagged?"
  
  For anyone else who has encountered this phenomenon, have you come up with any insights?
  
  EDIT WITH ADDITIONAL INFORMATION FOLLOWS:
  
  To the best of my knowledge, you can only see the ADULT tag via Amazon's API. You won't see it on the book's listing on Amazon.
  
  To see an example, search amazon for the author "Blake Cross". (The results are Not Suitable for Work!) I have no relationship to that author or what's published!
  
  To see the "ADULT" tag exposed via Amazon's API, go to http://www.salesrankexpress.com/ and enter Blake Cross as the author name. 
  
  The author/maintainer of Sales Rank Express explains his take on the ADULT tag in his FAQ at http://www.salesrankexpress.com/#adult - in short, he says it appears to be arbitrary and inconsistent. He concludes, "By contrast, a surprising number of Kindle books are blatantly pornographic without being labeled 'Adult'."
  
  Our own specific medium is electronic books (we stopped doing print books), Romance genre. We've concluded pretty much the same thing as the Sales Rank Express maintainer. It seems to be based on the book cover rather than the text content, and rather arbitrary. It seems to be more subtle things such as setting and situation, facial expression, and so on.
  
  To the best of our knowledge, as publisher, there are NO clear guidelines; the publisher is NOT informed when an offering is deemed "Adult."
  
  For something like Blake Cross's offerings, the reason for ADULT designation is obvious. The situation is far more subtle with a Romance-genre novel.
  
  The question remains: For anyone else who has encountered this phenomenon, have you come up with any insights?
upvoted_answer: Check your product descriptions for certain trigger words. See this comment:
  http://www.thepassivevoice.com/12/2013/amazon-is-making-it-harder-to-sell-bigfoot-porn-ebooks/#comment-155994