Reading headlines from the last year, it's tempting to imagine that podcasting suddenly emerged fully formed in the world of media. Within the last few months, entrepreneurs like Slate and "This American Life"'s Alex Blumberg both launched new companies that seek to capitalize on podcasting's popularity among listeners, and old stalwarts like NPR and Chicago Public Media have joined the fray with offerings of their own.

But before Blumberg's Gimlet Media got off the ground, before "Serial" lit up the iTunes charts, before Slate launched its own podcasting network, their creators were already working to develop an audience for the medium. And so was Radiotopia, a podcast network that arrived on the scene before the swell of publicity generated by "Serial."

Radiotopia, an initiative from PRX that got its start in November 2013 with the help of a Kickstarter campaign, was an early entrant to a growing field of companies that seek to bring high-quality audio storytelling to a vast audience. And today, the company is set to expand its offerings with the help of a $1 million investment from the John S. and James L. Knight Foundation. The money will be used to help the network add to its portfolio of shows and hire an executive producer who will provide editorial guidance to producers across the entire network.

"Just over a year ago, we launched this network, and — not just through our own efforts — the entire world has converged around audio and podcasting this past year in a remarkable way," said Jake Shapiro, the chief executive officer of PRX. "Many of those same trends are ones that we were watching when we first started planning to launch Radiotopia, and now they've come to full fruition."

During the last year, Radiotopia has grown in step with the growth of podcasting. When the network formally launched in February 2014, it saw an initial monthly download rate of 900,000 per month. Today, the network's shows are downloaded about 7.5 million times monthly, primarily by mobile users who get them through iTunes.

The network's offerings have expanded along with its audience, too. In November 2014, Radiotopia raised more than half a million dollars with a second Kickstarter campaign to add four shows to its portfolio, bringing the total to 11. Five of those shows are hosted by women, in keeping with the network's push to bring some gender diversity to podcasting.

Today's investment from the Knight Foundation represents the second time the grantmaker has funded Radiotopia. In February 2014, Knight committed $200,000 to the fledgling network to help its early development. The most recent investment signals that Knight — which has also invested in Gimlet Media and audio indexing startup Pop Up Archive — thinks there's a way forward for digital audio.

"We see a renaissance happening," said Chris Barr, director of media innovation for the Knight Foundation. "We know we're in a moment where a lot more people are listening to podcasts because the barrier to entry to listening to them has lowered. We have faster mobile broadband speeds, so people can stream and listen to these things on their phone."

For Knight, today's funding signals that Radiotopia has moved beyond the prototype phase and grown sufficiently large to warrant a two-year grant for a larger sum. Some of that funding will go toward a pilot fund, born from a Kickstarter campaign in November 2014, dedicated to backing new programs that aren't traditionally well-covered in public media.

Although Radiotopia intends to add shows with the Knight Foundation grant, the network hasn't set a specific quota or cap for the number of programs it plans to bring aboard, Shapiro said. Rather, the network will focus on picking podcasts strategically based on the quality of the shows and the commitment of their producers.

"Our idea is not to scoop a whole bunch of shows or double or triple the size of Radiotopia," Shapiro said. "I could see us adding several more this year, but the idea is to do it in a very intentional way."

Correction: A previous version of this post, relying on information from PRX, incorrectly stated Radiotopia programs are downloaded 6 million times monthly. In fact, the network's monthly downloads are now at 7.5 million.