Coke has partnered with Chinese marketing firm Pioco to broadcast commercials via Bluetooth-equipped cell phones through a network of thousands of hotspots the company has set up at Olympics stadiums, restaurants, hotels, clubs and other venues throughout Beijing and Shanghai.

Anyone with a Bluetooth phone in of one of Pioco's hotspots will be prompted if they want to receive content from Coke. If they accept, their phone will begin downloading the beverage giant's ads.

Coke, which has worked with Pioco for the last two years, is trying to take advantage of Bluetooth marketing to reach consumers at outdoor entertainment venues.

"Pioco has already enabled us to reach millions of consumers in hundreds of Chinese cities via Coke's Olympic Torch Relay Truck in preparation for the summer Olympic Games," says Michelle Yang, media director for Coca-Cola China. "We're projecting we'll reach millions more local and visiting international consumers over the course of the games."

Coke is an official sponsor of the Beijing Games.

For its part, Pioco touts conversation rates of 35% in previous Coke campaigns, with a conversion defined as when someone agrees to download content or advertising. At events such as the Olympics that encourage people to turn on Bluetooth on their mobile devices, conversion rates can reach as high as 65%, according to the company. (Pioco's hotspots are marked with special light boxes reminding people to activate Bluetooth.)

According to a recent interview with Pioco CEO Steve Chao by research firm Pacific Epoch, the company had installed 1,200 Bluetooth terminals so far in 2008 and planned to have 500 hotspots set up in Beijing before the Olympics.

By year's end, Pioco expects to have 15,000 terminals in five cities, which also include Guangzhou, Shenzhen, and Hangzhou. Chao estimated that more than 350 million people in China have Bluetooth phones, with especially high proportions of cell users in cities such as Shanghai.

Driven by huge markets in China and India, eMarketer projects the Asia-Pacific region will overtake the U.S. in mobile ad spending in four years. By 2012, mobile ad dollars will hit $6.8 billion, possibly outpacing desktop-based Web marketing in Asia. Cell phones often serve as the main interactive devices for large swaths of the middle class in China and India.