I found this fascinating quote today:
Search engine marketing and promotion companies, will look at the plan for your site and make recommendations to increase your search engine ranking and website traffic. If you wish, they will also provide ongoing consultation and reporting to monitor your website and make recommendations for editing and improvements to keep your site traffic flow and your search engine ranking high. Normally your search engine optimization experts work with your web designer to build an integrated plan right away so that all aspects of design are considered at the same time.What The Heck Is SEO, Jan 2009
You should read the whole article.

