With the inclusion of the podcast app in newer iPhone, and the success of series like Serial, podcasts are enjoying  rapid growth, says Ira Glass, the public radio veteran and producer of This American Life.

We spoke with Glass last week at the Digitas NewFronts where he pitched the marketing value of podcasts to a room of brand marketers and Digitas execs.

While precise analytics around listener engagement is more than a year off, the medium has produced valuable returns for early marketers like MailChimp.   He says that marketers have not tapped podcasts, but expects that to develop.

In the interview, Glass talks about a groundswell of interest in medium and entrance of a number of enabling companies and a surge of creativity. He says he has gotten personal inquiries about starting podcasts in recent days from actor/comedian Jerry Lewis and the writer Malcolm Gladwell.