From my journal at TheFeature:

Grafedia is a new form of multimedia graffiti developed by John Geraci, a student at New York University's Interactive Telecommunications Program, that transforms graffiti tags into hyperlinked tags for the real world. Grafedia is a word written on any physical surface that is linked to rich media content online. If you see a grafedia tag, you send an email message to that word "" and the related content is emailed to your mobile device, or anywhere else you receive mail.

Anyone can become a "Grafedia artist" by sending a word and the media file to the Grafedia server. For example, I created a Grafedia tag for the word "mahole." Just email and see what comes back!