In 2014, Serial upended everything we thought we knew about podcasts, rocketing to the top of any chart it landed on and proving that audio storytelling can have mass appeal beyond a devoted base. With its second season, Serial is shifting the paradigm for podcasts yet again—by expanding the medium beyond just audio.

Starting on Dec. 10, you could listen to Sarah Koenig’s recounting of Sergeant Bowe Bergdahl's capture by the Taliban, sure, but that was only one piece of the story. For the first time, the Serial team offered up other content in addition to the podcast. Shareable clips, photos, GIFs, interactive maps, videos of Bergdahl; all of it went out on *Serial'*s website, as well as its Tumblr, Instagram, Facebook, Twitter, and Vine accounts.

The traditional limitations of the podcast form create much of its appeal: Listening to a story without visuals feels intimate. Restricting podcasts to audio encourages a small, loyal audience—but it also poses a hurdle for increasing their audiences. There's no easy way to share snippets of audio files through social media, and no easy access to shows outside of the Apple Podcasts app; those steep barriers to entry have resulted in a vast untapped audience of not-yet-listeners. This is the year when the podcast medium will prove whether it can reach listeners beyond its largely white, wealthy, and educated core. Through experiments with multimedia and even new distribution models, we're about to find out just how far podcasts can spread. Serial is just the start.

The End of Apple’s Podcast Dominance

For any other medium, multiplatform availability is the default. You can catch up on episodes of your favorite TV drama on Netflix or Hulu (or your illegal download channel of choice), whether you’ve got an iPhone or Chromebook or Microsoft Surface. But for podcasts, distribution has been all but dominated by iTunes and the Apple Podcasts app.

(In fact, while the first season of Serial broke records for a host of reasons—compelling form and content, strong cross-promotion on This American Life—it also owes much of its viral success to the fact that two weeks before it premiered, Apple's iOS 8 update automatically installed the Podcasts app on all Apple devices. Suddenly, it only took four taps on an iPhone to tune in.)

Slowly, though, that virtual monopoly is changing. With season two of Serial, podcast episodes are seeing concurrent release on a non-Apple app—Pandora—for the first time.

Pandora product manager Scott Riggs first thought of bringing podcasts to Pandora at the height of the Serial craze; despite the show’s reach, Riggs knew that the majority of people who listen to music still have never been introduced to podcasts. (According to an Edison study from 2015, only 49 percent of Americans are aware of podcasts at all.) "Our vision was always to be additive to the world of audio stories," Riggs says. "Podcasting seemed like an easy transition for a music listener who wanted to listen to other kinds of content. What [Pandora] can do is bring this content in and offer it to those people, so they can listen without having to go through the hoops that exist today with podcasting."

The hope here is that by bringing these stories onto a platform like Pandora, we can open up this world of storytelling to a wider audience, who can engage with this audio in a way that they never could before. Pandora product manager Scott Riggs

To cater to listeners accustomed to three-minute songs, Riggs and his team break episodes into smaller chapters, unlike the hour-long episodes available on the Podcasts app. "From a streaming perspective, we think about it as a continuous listening experience—people will listen for a bit on their commute or at the gym," says Riggs. "Taking an hour-long experience and breaking it into chapters seemed like a seamless way for users to digest this content."

So far, Pandora offers Serial, and plans to distribute episodes of This American Life later this year. If the experiment works with these high-profile podcasts, Riggs wants to bring more shows to Pandora listeners, in chapter-sized form. "The hope here is that by bringing these stories onto a platform like Pandora, we can open up this world of storytelling to a wider audience, who can engage with this audio in a way that they never could before," he says.

Experimenting with Multimedia

If you want to respond to a ridiculous tweet, you can embed a GIF on Twitter. If you want to share your favorite moment from last night’s TV episode, you can upload a video on Instagram. But there’s no easy way to share podcasts, other than posting the external link to a full episode and explaining which part of it you like best. For a medium that relies on personal recommendations, that's an especially cumbersome problem.

"Podcasts largely rely on word of mouth," says Anne Wootton, co-founder and CEO of Pop-Up Archive, which transcribes podcasts, and Audiosear.ch, which makes them visually searchable. "It's much less common for people to come across an excerpt or a clip on Twitter or on Facebook."

But for podcasts to scale up, creators need to reach listeners outside of the echo chamber—and enable those listeners to share with their networks. "Fundamentally, for audio to become more of a mass medium," says Wootton, "shareability and accessibility are crucial." And if Serial is attempting to solve the accessibility through its Pandora experiment, the show is trying to expand shareability through multimedia.

By offering ways to share on social platforms, like episode previews on Facebook and videos on Vine, the Serial team is looking to convert its fans into evangelists. (Serial declined to comment for this article.) The first season spawned a barrage of message board speculation; if Serial can give its Season 2 audience something to post beyond #Mailkimp memes, the podcast could spread among a whole new audience of first-time listeners.

"The best marketing tool is always going to be word-of-mouth, and social media really lends itself to that," says Delaney Simmons, social media director for WNYC. "What if you could suggest a podcast to a friend over Facebook, like you would with a meme or a photo?"

Just by putting the best 15 seconds from a story over a JPG on Instagram, we've found tons of engagement. If we can find ways to put out audio that lives natively within those platforms, we can help audio files travel further than a click-through link. WNYC social media director Delaney Simmons

In the past six months, WNYC has experimented with posting audio clips on social media, including the first full-length episode embedded on Facebook, for Alec Baldwin's interview of Jimmy Kimmel on Here's the Thing. "Just by putting the best 15 seconds from a story over a JPG on Instagram, we've found tons of engagement," Simmons says. "If we can find ways to put out audio that lives natively within those platforms, we can help audio files travel further than a click-through link."

The Next Step: Social Audio

Serial and Pandora and WNYC are testing the waters of increased access and multimedia in podcasts, but other big players will dive in soon. Google Play plans to release its own podcast app sometime this spring, which will erase a roadblock for the world's billion-plus Android users. And you can expect offerings from podcast providers themselves in the coming months, as well; according to Wootton, Pop-Up Archive has worked on experiments with networks including Panoply, NPR, BuzzFeed, and Gimlet to develop ways for listeners to cut and share snippets of audio on social media.

To exist beyond establishment series like *This American Life *and Serial, the podcast medium has to find new listeners well outside its current audience. In this way, the medium's relative nascency gives podcasters an advantage—they’re used to experimenting when it comes to audio content. Now, they need to experiment with distribution across mediums. And in 2016, they'll have the platforms to prove they can.