First off, congrats on the web site. It is truly a study in clean, lean page code.
I've tried to understand the way the footer is positioned. It looks like a variant of the popular wrapper based method, with the article tag taking the place of the wrapper.
I was wondering if anyone has experience with Jeffrey Way' solution of fixed positioning?
Looks pretty promising (and simple) to me.
I had to add the box-sizing: border-box; option ( and the equivalent Moz. and Gecko variants for content within the footer to position correctly.
But in limited testing - it looks promising.