I've been digging around WmW looking for threads with links to articles in the media at large that tell about the benefits of SEO. I know that people have posted these links, but I can't remember the thread names.
I'm drawing a blank, too. But here's an article with some good quotes
....the Company could test heretofore-unknown consumer waters by using search engine marketing. Sending a printed catalog through the postal mail (if you could find a rental list of people looking for light bulbs) wouldn't be even remotely cost effective. But positioning the Company's products, so they appeared in related search engine queries might make sense.
Bonello notes all of this B2C business would have been practically impossible without the search engine marketing on the Internet.
Here are links to some very good newsletter resources. Since Search engine optimization and positioning is a dynamic industry, newsletters keep you up to date on changes and developments better than static articles.