Web-integrated VoIP vendors, still looking for their killer app, are nonetheless ready to start trying to squeeze out some revenues via advertising.

Jaxtr recently launched the Jaxtr Café site, a social network that includes voice and text ads. Jangl has started running ads with audio ad provider Pudding Media.

VoodooVox last week released MyVox, which lets Web sites integrate phone-delivered voice annotations into their Web applications. Rather than running audio ads inside the Web app, MyVox places ads on the “call-in” side of the equation, something it does today for more than 500 radio stations and calling card companies at a rate of more than 250 million calls — what it calls “voice impressions” — per month.

VoodooVox believes that while the appeal of ad-supported Web calling is likely to be mixed, existing information services such as MovieFone, 1-900 joke lines and 411-style directories may be a better model for driving “phone” traffic and audio ads on the Web. Add the Web's viral nature, and you could begin to generate enough voice impressions to build a real business.

“When we look back in the rearview mirror, we'll see that a lot of new, novel [Web-based] phone applications are being created,” said J. Scott Hamilton, CEO of VoodooVox. “It's just that I don't think a lot of these first-generation applications are the right ones. That said, there's something definitely interesting about adding voice to the mix at the Web application layer.”

VoodooVox's goal with MyVox is to serve 1 billion Web-enabled voice impressions per month by the end of 2008, charging advertisers a $20 CPM split fifty-fifty with developers — numbers that begin to make Web VoIP a real business.