Slides from a presentation on machine tags by Aaron Straup Cope. I highly recommend downloading the PDF for the bounty of links listed under "Reading List."
Tim Lucas is using machine tagging to aggregate Flickr pics from the "I work on the web" meme started by Lisa Herrod.
Yes, there is a reason why I'm using this machine tag. Watch the next release of Last.fm for machine tagging goodness on events.
Machine tags will now be available through the Flickr API (that's triple tags to you and me).