Where on the Page do Ad Units Work Best?
The best place to put the ads varies page by page and at the risk of sounding like a broken record, this depends again on the individual content. However, there are again some general ideas that Google can provide us with on what works best across the whole spectrum. Ad Units that are immediately visible outperform those you need to scroll to. Ads placed near rich content and navigational aids usually do well because users are focused on those areas of a page. For a general idea see this heat map which illustrates the ideal placing on a sample page layout. The colours fade from dark orange (strongest performance) to light yellow (weakest performance). For a more detailed look into formatting and placement issues, you can read the complimentary article, Formatting and Placement of AdSense in Content.
