Pharmaceuticals giant Johnson & Johnson and General Motors Corp.'s Chevrolet car brand recently ran mobile marketing campaigns using in-call audio ads, SMS and mobile Web sites.

For the deployment of the audio ads, both brands tapped the VoodooVox In-Call Network, which functions just like traditional online banner networks, except that rather than integrating into Web sites, its publishers are high-call-volume companies. VoodooVox inserts audio ad spots directly into the call streams of its publishers, which include calling-card companies, 411 services, call centers, radio stations, VoIP providers and various Voice 2.0 applications.

"Chevrolet was looking to engage the youth market in a street team summer-long promotion," said Greg Wester, vice president of product development for VoodooVox, New York. "They engaged callers in several different Q&As via SMS, and if they qualified, they became part of the Chevy street team."

VoodooVox helped Chevrolet to target DMAs across the Midwest, including Chicago; Indianapolis; Cleveland, Columbus and Cincinnati, OH; Minneapolis/St. Paul; and Grand Rapids, MI.

"They said they wanted a particular audience, teens and young adults, and we can find that demographic across different publishers," Mr. Wester said. "There are a variety of social networking sites that represent a great target market for those campaigns.

"Based on the target audience, the audio ad gets played across a variety of our publishers," he said. "Our media ad was a 20-second audio clip inserted into several types of phone calls."

Rather than have to text in to opt in, consumers heard the call to action "Press 9 now" to opt in.

"We grabbed that person's phone number, passed it on to the mobile agency they were working with and the consumers were opted in," Mr. Wester said. "We deployed the audio ad when consumers called into local radio stations or used a prepaid calling card.

"It was a very targeted audience, and almost 10 percent opted in, which shows the power of audio branding," he said. "Chevy was looking for a certain set of numbers, and the response rate certainly validated that media -- they were happy with it."

For the J&J campaign, the goal was to get a certain number of the target audience to fill out a form on the company's WAP page.

German mobile services provider Mindmatics tapped VoodooVox on behalf of J&J to drive a free trial offer via the mobile phone.

The J&J product offered was One-Day Acuvue Moist Lenses with Hydraclear Technology.

"They tested our in-call media ads against other media types, and we compared quite strongly, and we're currently in discussions for future business," Mr. Wester said.

"They wanted to reach young adults, so they could hear the brand message and the offer," he said.

As with the Chevy campaign, the call to action urged consumers to press 9 to get the link to the mobile Web site and opt in to the campaign.

VoodooVox created a Young Adult Channel on the In-Call Network that let MindMatics customize the audio ads by phone type and directly target mobile phone consumers by location and other factors.

The campaign got response rates between 4 and 5 percent.

In 2006, VoodooVox claims that the overall click through rate for the In-Call Network was 12 percent.

"When you run a mobile marketing campaign, where do you get your media support from?" Mr. Wester said. "In-call media is another option and it has certain benefits, such as simplicity for the user, especially when doing text messaging, there's a 30-to-one reduction in what you have to press to opt in.

"When you compare a banner ad to an audio ad spoken directly into the consumer's ear, there's also a greater branding impact even for those who don't participate," he said. "Studies show that awareness of an event or brand was doubled by having someone exposed one time to an audio ad.

"People are really paying attention when calling and opt-in rates are very competitive with other media."