The basic Conversion Rate equation is online sales or leads divided by traffic.
When you get a lot of bad traffic, your conversion rate drops, as would be expected. However, if you get traffic that is well qualified, you generate more sales, more leads for less effort.
Search engine optimization (SEO) is the process of telling the search engines what your Web site is about, so that people who are looking for things you offer find you (and everyone else goes somewhere else). There are few online marketing strategies that deliver such highly qualified traffic over long periods of time with no advertising buy.
Carolyn Shelby took PubCon Masters Training attendees through the basics of SEO. She is one of the most respected speakers at PubCon, and if you get a chance to see her, I strongly recommend you sit in. She is the source for Chicago SEO.
Here are my notes from her presentation captured using Instagraph Infograph technology.