It's official. On January 19, 2012, Google announced that it will penalize sites with pages that are top-heavy with ads. Such WebPages will either disappear from Google Ranking or move down significantly. Google says, "Be mindful of having too many advertisements on any of your pages, in relation to "meaningful" content. There seems to be a direct correlation between the number of advertisements on a page (especially above the fold advertising), and the overall ranking of a page. Make sure you have plenty of quality, relevant content to balance out your web pages." The change called the "page layout algorithm" takes direct aim at any site with pages where content is buried under tons of ads.
Google Continues: "This update is designed to reduce rankings for low-quality sites - sites which are low-value, copy content from other websites or sites that are just not very useful. At the same time, it will provide better rankings for high-quality sites - sites with original content and information such as research, in-depth reports, thoughtful analysis and so on. It is important for high-quality sites to be rewarded, and that's exactly what this change does."