A harbinger of the “geospatial web,” Yellow Arrow began in 2004 as a street art project on the Lower East Side of Manhattan, eventually growing to include participants in 38 countries around the world. The project prefigured Google Maps, Flickr, MySpace, Facebook, and geo-locative applications on smartphones by suggesting that social software, coupled with mobile devices and photography, could serve to radically redefine our conception of place. Stanford archaeologist and cultural theorist Michael Shanks writes that Yellow Arrow was an early example of “deep mapping cultural experience—a cartography of the intimate, the everyday, the monumental, the ephemeral, the epochal.”

From the original site:

“Participants place uniquely-coded Yellow Arrow stickers to draw attention to different locations and objects—whether a back-alley mural, a favorite dive bar, or a new perspective on a classic landmark. By sending an SMS from a mobile phone to the Yellow Arrow phone number beginning with the arrow’s unique code, Yellow Arrow authors essentially save a thought on the spot where they place their sticker. When another person encounters the Yellow Arrow, he or she sends its code to the Yellow Arrow number and receives the message on their mobile phone. They can then reply to send a message to the author. By collecting and sharing places of personal significance, this public collaboration expresses the unique characteristics, personal histories, and hidden secrets that live within our everyday spaces.”