Consider the contradictions surrounding the subject: An April 2005 Pew Internet & American Life study estimated 6 million people have downloaded a podcast while a Bridge Ratings study in November of 2005 -- yes, seven months later -- puts the number at 4.8 million. An eMarketer report from March of this year puts the total number of podcast users at 10 million but pins active podcast listeners -- who download at least once a week -- at 3 million.
There's even less agreement about how quickly the podcast audience will grow. A Forrester study just released estimates podcast listners will total 12 million by 2010. EMarketer predicts the active podcast-listening audience will be 15 million but the total market will be closer to 50 million and a Bridge Ratings study published in November of 2005 is also bullish, estimating the podcast audience will grow to between 45 million and 75 million by 2010.
PodTrac, Podbridge and PodShow are all trying to help advertisers get a better grasp on how many people are listening and what the audience looks like.
"It's really difficult to say exactly how many people are listening," said Mohan Renganathan, associate director of digital strategy at MediaVest. He and his cohorts see the emergence of podcast networks that aggregate an audience as a way to make the medium more palatable to advertisers. "You're seeing a Long Tail phenomenon where you have hundreds or thousands of podcasts with a couple thousand listeners," he said. "In isolation, they may not be advertising viable but when you start aggregating them together, all of a sudden it makes sense."
How many are actually listening?
Eluding marketers are the questions of how many people are actually listening to podcasts, because they're primarily delivered via really simple syndication, or RSS, and automatically delivered to a browser. Just because a person subscribes to a podcast doesn't mean he or she listens to every episode. And who are those listeners anyway?
One network, Podbridge, is offering information about whether and when a listener heard an embedded ad. It uses a passive technology to track listening: When a listener subscribes to a podcast within the PodBridge network, it installs a plug-in, a la Macromedia flash, that asks basic demographic questions. The plug-in puts a header into the user's podcast content and captures the time at which the content was played and whether a user listened long enough to hear the ad.
Podbridge has about 35,000 people listening to its network and using the plug-in and has contracts with Clear Channel, the BBC, Consumer Reports and Military.com, said its founder and CEO, Murgesh Navar. It primarily targets established content publishers rather than the mom-and-pop upstarts that populate much of the podcasting space.
Pattern and demographics
"You find a certain pattern and demographics. Some people tend to listen in the morning and some people listen at night," said Mr. Navar, who signed Ronning Lipset Radio, which sells online radio ads, as its third-party ad vendor. "Because we know usage patterns we can slot an ad that's likely to be heard in a particular daypart."
Another network, Podtrac, has signed to its network more than 1,500 podcasts -- some with a few hundred listeners, some with more than 300,000 -- since November. Some of its more popular podcasts include "This week in Tech" and the Harry Potter-themed "Mugglecast." The deal? Podtrac provides third-party measurement and ad insertion for a 25% cut of the advertising revenue. Ads for HBO's new show "Big Love" and for Castrol motor oil have aired on the Podtrac network.
Podtrac also provides demographic information about a podcast's audience through a survey that has so far yielded more than 40,000 responses. Podtrac then overlays its survey responses with responses to Mediamark's Survey of the American Consumer, Mark McCrery, Podtrac's CEO and co-founder, explained. "We're noticing that these podcast listeners and viewers are highly educated. They are predominantly male at this point. They have high incomes and they buy a lot online."
Needs to be seamless
The first company to enter the space was PodShow, launched by Adam Curry and Ron Bloom. It delivers national advertising and sponsorship across its network and recently executed a cross-network sponsorship for GoDaddy.com that included audio, video and host endorsements from more than 50 of PodShow's most popular podcasts. Hosted ads are turning out to be one of podcasting's biggest boons, thanks to the affinity the listeners often have for the host.
One of Starcom's clients, Sara Lee's Senseo coffee brand, had particular success with live reads on Adam Curry's "Daily Source Code" podcast, which many credit with launching the podcasting phenomenon. Starcom knew Mr. Curry was a coffee drinker, since he often spoke about it on the show, and contracted him to push the product on the show.
"If you're going to integrate into a program it needs to be seamless," said Fletcher Whitwall, associate media director at Starcom USA.
At this point, much of podcasting's advertising been done on a sponsorship basis, in which a marketer commits a set amount of dollars against an estimated number of downloads or impressions. Marketers can then back into a cost-per-download -- a number that's ranged between a couple cents to $2.