• Fortune via CNNMoney.com, Wednesday, January 16, 2008 11:15 AM

Marketers are getting ready to storm one of the few remaining ad-free zones with an Internet company now testing "in-call" advertising for Web phone service. Last month, privately held firm Jangl began making some customers listen to a short audio spot while waiting for their call to connect. Another company -- Jajah - -is set to launch in-call ads this year. Customers opt into that service and can get a break on their phone bills for listening to ads.

While similar to the ads consumers hear while on hold with things like airline reservation services, Jangl and Jajah can actually target the ads they serve callers. "We know this is kind of bold," says Jangl founder Michael Cerda. "But these are bold times." The technology is so new that many ad agencies haven't even heard of it and some that have are skeptical.

"The first question I would have is how is privacy being handled," says Angela Steele, a mobile marketing vice president at ad buyer Starcom USA. "People need to know that by using the service, that information can be used for advertising."

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