Sometimes two people write about the same thing.
I saw the ghost shelf on hank lee and thought it was curious, I typed "invisble book shelf" into google and the third result down was this: http://www.boingboing.net/2006/05/06/invisible-bookshelf-.html and that linked to Umbra conceal shelf site.
Gordons site links to another that wrote about how to make an invisible shelf back in January and the post at boingboing was written in May.
I might be a rude cunt but my thoughts and posts here are my own views. I'm happy to give a shout to someone else who has written about this but for the fuckwitt who commented to the post - gordon's blog wasn't my "source". My source was Hank Lees hot list and a google search which took me about 90 seconds.