Chasing SEO on various media platforms has been known as Chasing the Long Tail...
How do you use this powerful concept... longer search terms = more likely to convert.
OK what does that mean?
Read this short paragraph by Ian Lurie
http://www.portent.com/blog/seo/long-tail-seo-101-defined.htm
Get it... the longer and more specific the search term the more likely the consumer is actually closing in a decision to purchase (convert)
Long Tail terms comprise as much as 70% of all searches!
The demand curve for Head (short) vs Long Tail graph shows just how important focusing on these 2+ phrase searches really is
Read More on Long Tail conversion at
http://www.seomoz.org/blog/illustrating-the-long-tail
Using Long Tail terms that are 4 words optimizes (converts) the best
Look at this treasure trove of SEO data
SEO Graphs and Charts regarding from SEOMOZ