Through the new MyVox service, end users will be able to do things like add voiceovers to online slide shows or spoken directions to Google Maps. When users record voice content via phone, they'll hear a 10-second ad served by VoodooVox's audio ad network. The company will split the ad revenue with developers.

"We're giving developers the ability to turn the phone into a microphone (for consumers)," said VoodooVox CEO Scott Hamilton. That capability in turn will help generate more calls for the company's existing business of placing audio ads in calls by consumers into radio stations, TV networks and 411 and calling card services.

"We're doing this because we want to take the phone calls we know will come through MyVox and package them with the other voice avails and build our network to where we're handling 1 billion calls a month," said Hamilton, who equates calls with Web page views. Currently, the company's In-Call Network is trafficking about 250 million calls monthly.

Advertisers using the network to date include MSN Music, Toys 'R' Us, Pfizer and Latin music site Batanga. Ads are inserted between prompts in calls and can be targeted by demographic factors such as age and gender, geographically (by area code), and by time of day. Callers press a phone's "9" key to learn more about a product or service or participate in a promotion.

With a click-through rate of 12%, VoodooVox is typically charging a CPM of $5 to $10 that rises to about $20, effectively, if callers take certain actions tied to campaigns. About 60% of its call volume comes through mobile phones, said Hamilton.

In-call advertising has expanded with the emergence of mobile media in recent years. Other startups involved in the nascent sector include Jajah, Apptera and Jangl. VoodooVox has received $13.5 million in venture funding so far from backers including Steamboat Ventures, the investment arm of the Walt Disney Co., Apax Partners and Softbank Capital. The company projects 2008 revenue of $5 million to $10 million.

For the MyVox service, the company wants ads to reflect the Web 2.0 emphasis on blending media and advertising by offering sponsored snippets of content or promotions. "We have to figure out what ad types to drop into MyVox so it appears as ad-supported media as much as possible so it's an immersive, entertaining experience," Hamilton said.

To help get developers on board, VoodooVox is offering up to $75,000 in prize money for creating innovative and popular voice-enabled applications.

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