William Slawski wrote a very good entry on the importance of page layout in SEO. To emphasise his point he pointed out to the patent application filed by Kesari and Anandsudhakar in August of 2006 and that was recently published last month. The patent application entitled “Techniques for approximating the visual layout of a web page and determining the portion of the page containing the significant content” is obviously used to help Yahoo! find the parts of a web page that contains the more important content. It seems that at least Yahoo! does determine the importance of the contents of the page based on the page layout, and if Yahoo! does this I guess it is safe to conclude that Google and the other search engines have their own if not similar method of determining the importance of the content based on page layout.
What this means for SEOs is simply that we should emphasise to clients the importance of placing keywords and phrases in the main part of the site. It is also more important to try to get linked to by other sites not just on the sidebar but the actual main section of the site. In short, it is better to be mentioned in a blog post than to be included in a blogroll and most definitely over being placed on the footer. As the abstract of the patent says
So remember it is not only the position but also the amount of content in that certain position that affects how search engines interpret the importance of that section of the page.
Furthermore, though most of us do this already, always remember that it is good practice to emphasise keywords by using a larger font size, putting it in boldface, or changing its color.