All the Case Studies in this Case Study Section are based on Organic Placement for the top 4 Search Engines GOOGLE, YAHOO!, MSN and AOL Search. As you can see from the pictorial to the right - the top 4 Search Engines are where you want your web site to be seen - preferably in the Organic Placement Section and not just the PPC (Pay Per Click) Sections of the web site listings. These 4 Search Engines make up approximately 95-97% of all the web surfing public. So - when you get E-mails from SEO companies saying - Your Web Site Isn't Being Seen - just know that if when you can go to any of the top 4 Search Engines and type in Search Phrases appropriate to your web site and you find your site being listed - You Are Being Seen. The other hundreds of search engines other than the top 4 make up so little of the web surfing public, they simply aren't all that impacting. Recommendation: It is recommended that before you move on to the different Case Study Placements to the right, that you first review the Online Learning Search Engine Course Study to make sure have a solid understanding of the basic search engine concepts found documented in each Case Study section.