Podcasting ads: Is 15 seconds the limit?

Maybe there are tons of them out there, but I had yet to come across a podcast with a radio-type ad at its beginning—until today, when I checked out Slate’s new offering. The daily feature has Andy Bowers, a former NPR guy and now a Slate guy, reading one or more stories posted to Slate.com that day. On the MP3 I heard, Andy gives a 45-second introduction, which is followed by a 15-second spot for the Chrysler 300, then back to Andy, who reads the story. Whether or not online content read out loud makes for a compelling podcast is debatable. You can read what Slate says about its new feature here (in a block of text interrupted by a Vonage ad). But in terms of the 15-second spot—that seems a reasonable price to pay for a free podcast. And more important, it might be a short enough time that people won’t bother fumbling with their iPods to fast-forward through it.