This graphic below and the post it links to are by Brian Gardner of StudioPress, the company who creates the stellar Genesis framework which we use on most of the sites we make. See also this previous post.
And speaking of Genesis
The Bones Responsive/HTML5 Starter Child Theme for Genesis is now free (was $5). Check the excellent documentation in the functions.php file; great for getting up to speed on using the Genesis framework.
Thank You WordPress graphic designed by Brian Gardner.