Unfortunately no info on Wikipedia as yet. Graffiti Markup Language is an XML based way to record and store tags by X and Y axis, with time creating the Z axis. This open format is compatible with any other GML interpreter, meaning you can explode your tag into a giant laser or store in a database filled with legendary graf artists. A new door is opening on the underground art world.
Want to check it out for yourself? You can with DustTag, an iPhone app "designed for graffiti writers that visualizes the motion involved in the creation of a tag. Motion data is recorded, analyzed and archived in a free and open database, 000000book.com, where writers can share 3-D animated representations of their hand styles." Dig deeper at http://graffitianalysis.com/
