Blue Apron, Casper, Squarespace, Zip Recruiter. You’ve heard the names over and over again while listening to your favorite podcast. And let’s not forget about Mail Chimp—the podcast ad so popular it was was satirized on Saturday Night Live.

The man who brought listeners Mailchimp (or is it Mailkimp?) is David Raphael, president of  Public Media Marketing, an independent Chicago area firm that places sponsors with major podcasts such as Serial, This American Life, The Joe Rogan Experience, and America’s Test Kitchen.

Raphael has spent his career selling ads, first for commercial radio and TV, then for Chicago’s public radio station WBEZ, and now for podcasts. Like many of the companies he works with, he was an early adopter. “I started the company in 2010, long before podcasting is what it is today,” Raphael explains. “But the potential was there to reach out to a listener who is incredibly engaged to listen to this specific content.”

Within a few years, his firm became the first to sell a serialized podcast and add integrated advertising content. That serialized podcast was, of course, Serial, an offshoot of This American Life. Raphael signed the email marketing service MailChimp to sponsor Sarah Koenig’s podcast for its first season in 2014 with the assumption that it would be a moderate hit. “People thought MailChimp got a good deal—a viral spot in a hit show,” he recalls. “But they took a big risk on our size show with their size company. We projected to do just a percentage of what This American Life would do, but it was explosive.”

Serial had 102 million downloads in that debut year. “[It] proved the currency of the medium,” Raphael says. “Podcasting was this nerdy thing that was all of a sudden doing Super Bowl numbers. And what that meant for ad sellers is that we were having conversations with people that wouldn’t have taken our calls before.”

The “Serial effect” has also changed the way we listen. Podcast ads, or spots, come with the territory. And when Joe Rogan spends the first seven minutes of his show—yes, seven minutes—talking about Meundies.com, there’s a good chance listeners may not skip through it. They might even transfer  their positive feelings about the host onto those undies.

Raphael credits that to the connection between podcasts, hosts, and their listeners. He encourages his hosts to personally try every product. “Whether it’s an endorsement doesn’t even matter,” he explains, “just the host saying the name and talking about the brand to the listener is amazingly effective.”

Podcasts are still dominated by direct-response advertisers that want to track clicks via promo codes and custom URLs, but more and more, Raphael is working with brand advertisers like North Face and Scion. “For them it’s more about the affinity and image,” says Raphael. “They want their message tied to that brand.”

And you can expect the creative to follow suit, with out-of-the box promotions like fully sponsored episodes and narrative content. Because like a Don Draper of the podcast world, David Raphael is trying to teach the world to sing, or rather, buy a mattress.