Tagaholic - I Am Machine Tag And So Can You
http://tagaholic.me/2009/04/14/i-am-machine-tag-and-so-can-you.html
husk.org. a flickr machine tag browser.
http://husk.org/code/machine-tag-browser.html#tag=accessceramics:glazing=barium_carb.
Adactio: Journal - Machine Tags of Loving Grace
http://adactio.com/journal/1277
"I’ve started to implement this machine tag format here. If you look at my last post—which has a whole list of books—you’ll see that I’ve tagged the post with a bunch of machine tags in the book:isbn format."