A thread at WebmasterWorld talks about how one can get more relevant Google AdSense ads to display on their pages. Often, when you just put up AdSense, the AdSense spider may be confused about what your page is talking about. The code might be cluttered with navigation content, footer content, other ads and other information, where what the page is actually talking about is not the same as what the AdSense ad is targeting.
So what can you do?
Simple, use "Section Targeting." What is it? Well, AdSense explains that it allows you to define "sections of your text and HTML content that you'd like us to emphasize or downplay when matching ads to your site's content." You can tell AdSense, this is the content that is critical to the page. Google introduced Section Targeting in October 05'.
How do you do this?
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) -->
Forum discussion at WebmasterWorld.