Google made some AdSense program policies updates; The first is program policies page is revamped with reorganized content and updated layout to make it easier to read and navigate. Here’s content updates:

• Misusing Google logos, trademarks, or other brand features in the page content or URL is prohibited.
• ads may not be formatted in a way that makes them indistinguishable from other content on the page where they appear.
• Ad placement in emails and email programs may not be placed.
• Other Google products' policies: publishers aren't permitted to place ads, search boxes, or search results on, within, or alongside other Google products in a way that violates the policies of that other product or service.
• Finally, we've added more information to the 'Webmaster Guidelines' section and created a new 'Traffic Sources' section.

More info: AdSense program policies page