Google Searches and SEO Marketing

Google is used for at least 70% of Internet Searches. Yahoo is a very distant 2nd with about 10% of the Search market and MSN barely has 5% Market Share. So one of the first questions in approaching Search Engine Optimization is, "Why bother with Search Engine Listings anywhere other than Google?".

If Google Listings will generate the best results for me, what is the difference between Generic Search Results and Pay Per Click?

Search Engine Listings

Directory Listings

Organic Search

Pay Per Click