INFOGRAPHIC: How Big is the SEO industry on the Internet?

Since Google became the most popular search engine the SEO industry has grown exponentially year after year. Since the term was coined in the lately nineties, this industry has taken off.
Today there are million of searches every month, more are more people are interesting in Search Engine Optimization. Because of that interest, there are hundreds of books on Amazon.com, thousand of experts on Twitter, blog posts, etc.

So, this infographic is aimed to answer questions like: How big is the SEO industry? Which one is bigger: social media,ppc or SEO? Which are the top SEO terms? How many SEO books are available on Amazon.com?
This Infographic is Published by BlueCaribu