Search engine optimization, or SEO, is big business. Big enough to get a mention on close to 900 million websites, and to be the focus of 164,000 YouTube videos.

Spain-based internet marketing company BlueCaribu recently did a review of SEO resources online. And some of the results are astonishing. India, for example, is the nation most interested in search engine optimization. Germany, hardly at all.

Search engine optimization, of course, is the black art of ensuing that your website bubbles up to the top in organic or unpaid search engine results. It’s also getting harder and harder to accomplish, as Wordstream recently showed.

Other fun facts? Amazon has almost 3,000 books on SEO. 13 million blog posts have been published with “SEO” in the title. And Twitter averages almost 250,000 monthly tweets about SEO.

See all the details in the infographic below:

Image credit: Nasirkhan/ShutterStock