Thanks to the Web, cell phones, and tools like QR codes and text messaging, one of the oldest ad media is becoming interactive. According to ZenithOptimedia, the world's marketers spent $28 billion last year on outdoor advertising (i.e., billboards), and it forecasts spending in the category to grow 4% in 2010. Outdoor ads are everywhere—on buildings, sanitation trucks, taxis, bus shelters, phone kiosks, and even gasoline nozzles. The big change is that signage is becoming interactive at the consumer's request. At a time when consumers have become increasingly mobile and overloaded with information, the outdoor ad industry is touting the billboard (the updated version as well as the old standby) as the last powerful way to reach a mass audience efficiently.

Consumers can interact with outdoor ads with their smart mobile devices and download music, play video games, watch movie trailers, or purchase products. Signs can send a digital coupon to cell phones, and they may soon start addressing us by name. Marketers want interaction and engagement with consumers. Outdoor advertising blended with QR codes and text messaging provides immediate and measurable results.

Let's look at examples that are taking hold in today's market that blend signage with mobile.