Within the Google AdSense program you can use section targeting to suggest sections of your contents to pay attention to and which parts to ignore when matching google ads to your site's content.

To implement section targeting, you'll need to add a set of special HTML comment tags to your code. These tags will mark the beginning and end of whichever section(s) you'd like to emphasize or de-emphasize for ad targeting.

The HTML tags to emphasize a page section take the following format:
<!-- google_ad_section_start -->

<!-- google_ad_section_end -->

You can also designate sections you'd like to have ignored by adding a (weight=ignore) to the starting tag:
<!-- google_ad_section_start(weight=ignore) -->

Visit Google's AdSense support pages for more help getting started with section targeting.