Street graffiti eventually gets cleaned up and sandblasted away. Sure, you can take pictures of the piece when it's done, but there's nothing like watching a piece as it is being written. Now there is software that captures the essence of the tag in motion. Artist/programmer Evan Roth designed a system called Graffiti Analysis 2.0 that records a street artist's hand gestures while writing.
It's an open source project, and graffiti artists are invited to capture and store their own tags. Some influential artists have had their tags captured so far: SEEN, TWIST, AMAZE, KETONE, JON ONE and KATSU.