http://www.otherthings.com/grafarc/

A group of photographers and artists are documenting the accretion of the 'underground' urban landscape through graffiti art. Based in San Francisco, but also looking at graffiti in Los Angeles and New York, Cassidy Curtis and his team at Graffiti Archaeology document the changes through time of graffiti art at several tagging locations. All of the photographs are then 'photoshopped' together, placed in sequence, and made freely available via a custom flash program on the web. Arresting our web-enhanced gaze, it is a visual record manifesting what is routine and intimate, yet often simply hurried by.