Yellow Arrow is a global public art project in that began in New York, New York but has now spread globally. Yellow arrow stickers can be obtained from their website and placed anywhere in the public realm. When encountering a sticker on the street, one can send the unique code printed on it as a text message

Short message service

Short Message Service is a text messaging service component of phone, web, or mobile communication systems, using standardized communications protocols that allow the exchange of short text messages between fixed line or mobile phone devices...

 to a particular phone number. Moments later a text message will be received with a message left by the sticker's original owner.

The Yellow Arrow symbol means ‘there’s more here: a hidden detail, a funny story, a memory, and a crazy experience.’ Each arrow links digital content to a specific location using the mobile phone. As an underground phenomenon, the project has grown a vibrant and tight community internationally. As of November 2008, 7535 Yellow Arrow stickers have been placed in 467 cities and 35 countries.
Since appearing first on the streets of Manhattan's Lower East Side in May 2004, Yellow Arrow has been featured in The New York Times, Wired Magazine, Newsweek, The Washington Post, The Boston Globe, CNN and NBC, the London Times

The Times

The Times is a British daily national newspaper, first published in London in 1785 under the title The Daily Universal Register . The Times and its sister paper The Sunday Times are published by Times Newspapers Limited, a subsidiary since 1981 of News International...

, Politiken, Liberation, Diari de Barcelona, and de Volkskrant. Yellow Arrow was also featured in Lonely Planet's Guide to Experimental book series.