Boston.com reports

One art project, Yellow Arrow, based in New York City, has developed a system where people can place yellow stickers in the shape of arrows around the city, stating that they have something to say about that particular location. Each arrow, which is ideally placed in a location that holds significance to the person, has its own unique code that can be sent to a mobile phone via text messaging, allowing others to read the message that was left.

I wonder how many people will actually type in codes. But the essence of the idea is clear: provide location-specific content that conveys a particular situation to the visitor.

Via ACM news service.