Keyword
ranking
in Google
The value of a top keyword ranking on Google is different from that of Yahoo or MSN. Every engine gets a different volume of searchers, a different quality of searchers and a different intensity of searchers. Each of these plays a role in determining the value that a top ranking provides.
Market share: Market share is the most common measure of the value of a search engine. Google is by far the most popular search engine receiving almost 50% of all searches performed online.
Quality of searches performed: Because Google is the biggest engine that everybody cares about most, they probably also have one of the lowest percentage of quality of searches performed. A good portion of Google search is business owners, executives and employees performing power searches. That is, searching just to see where they come up in the keyword ranking. Add this to similar searches performed by the SEO provider and/or consultants and employees, vanity searches can really start to add up.
Those same power searches are also performed on Yahoo and MSN, but not to the same degree. Remember, Google is the place to be so that's where the higher percentage of power searches are performed. However, even with the number of power searches performed, if you look at traffic stats, Google probably still provides more search volume to your site. In this case, market share outweighs search quality.