Here is an email I received from Adsense today:
While reviewing your account, we noticed that you are currently displaying Google ads in a manner that is not compliant with our policies. For instance, we found violations of AdSense policies on pages such as http://www.ibookdb.net/book/78456.
As stated in our program policies, AdSense publishers are not permitted to place Google ads on pages with adult or mature content.
Please make any necessary changes to your web pages in the next 3 business days. We also suggest that you take the time to review our program policies (https://www.google.com/adsense/policies) to ensure that all of your other pages are in compliance.
Once you update your site, we will automatically detect the changes and ad serving will not be affected. If you choose not to make the changes to your account within the next three days, your account will remain active but you will no longer be able to display ads on the site. Please note, however, that we may disable your account if further violations are found in the future.
Thank you for your cooperation.
The Google AdSense Team
As soon as I got this email I removed all Adsense ads from ibookdb and replaced them with YPN because currently I have no means of turining off a particular ad for a particular page and I can’t ensure that I find all adult books on ibookdb reliably and accurately.
Also, this same book is displayed on many other sites with Adsense showing on the side, so I emailed Adsense support with links to other sites as proof. Some of these other sites are a lot larger than ibookdb, so I’m hoping that Adsense will just let me use those ads because after all the adult content is in the book, a limited preview of which is available to anyone at Google Books, and not on ibookdb.