Some page content can give Google’s AdSense the wrong impression of what your page may be about. On a page with multiple topics, your AdSense ads can come up with ads that are neither relevant nor profitable. To get around this problem, Google AdSense has a little known feature called “Section Targeting”.
To particularly emphasize a section, enclose the text in these tags:
<!– google_ad_section_start –>
The text to be emphasized is here
<!– google_ad_section_end –>
To have a section of text ignored, use this variation:
<!– google_ad_section_start(weight=ignore) –>
Text to ignore goes here
<!– google_ad_section_end –>
There is currently no limit as to how often you can use these tags. However, it may take one or two weeks before you see any changes. It is important to give AdSense big chunks of text to work with – avoid giving sections of text that are too small.