• by Alex Miller , September 22, 2006

Advertisers may be intrigued by the podcast, but assessing its ROI hasn't been easy. Many subscribers use services like iTunes, which means they're not going to dedicated Web sites to download each new episode. So the conventional metrics offered by Web hosters aren't leveraged.

One solution comes from Arbitron, which says its Portable People Meter (PPM) tracks podcasts. Audio files are embedded with an inaudible signal, which can be processed by the PPM - a small device carried by surveyors picked by Arbitron. The gizmo was originally created to track traditional radio.

But the Arbitron approach provides only a sample. The elusive killer app would track any and all podcasts and measured more completely. Michigan-based Oneupweb, a search engine marketing firm, says its new PodTractor service does just that.

"It's been a tough nut to crack for anyone, and no one has done it," says Oneupweb CEO Lisa Wehr. "We needed it ourselves and couldn't find anything, so we sat down to figure out how to make it happen."

Wehr says PodTractor can identify iTunes podcast downloads and track podcast subscriptions. One wrinkle: The podcast has to be hosted by Oneupweb to enable the tracking mechanism.