In October 2014, 10 Indianapolis school board candidates filed on stage in a public library and participated in a debate in front of an audience of concerned voters. Nothing too unusual there. Except for the fact that no one was planning on hosting a debate until Chalkbeat, a local nonprofit news organization focused solely on education, stepped up. (Full disclosure: I started working at Chalkbeat two weeks ago.) With Chalkbeat organizing, major media stepped in to broadcast and cover the debate.

The result: People in Indianapolis who don’t live and breathe school board politics had a solid source for making sense of the field, even if they only looked for information about the candidates while walking into their polling place.

General interest media used to serve that need, but with newspapers cracking under the strain of trying to be all things to all people, wide gaps are being left in their wake. News sites with a single-minded focus on specific topics have been filling those needs on critical issues for some time now. What’s new is their audiences are diversifying and broadening.

Beyond sources and subject-matter obsessives, verticals are now reaching casual news consumers.

Here’s what happens next: 2016 will be a year of growth for subject-specific publishers, as broader audiences use single-topic sites for deep expertise on the issues that matter most to their families. Verticals are growing up.

Some sit within larger companies like Vox or even The Boston Globe. Others stand as independent companies, from the smallest hyperlocal neighborhood blog to flourishing startups like Well+Good, Food 52, and Skift. As we know firsthand at Chalkbeat, the standalone nonprofit news sector is also rapidly growing, offering essential reporting that keeps the public informed about less commercial subject matter, including public education, health, criminal justice, and the environment.

It’s not going to be easy to make more of the deep expertise from these vertical news organizations accessible to the most casual audiences. But that’s the work that awaits us in 2016.

And as the audience for single-subject news sites grows in 2016, the organizations themselves — commercial and nonprofit alike — will become more sustainable. Expect to see all of these groups bringing in revenue from a more diverse set of sources, running crowdfunding campaigns, putting on events, throwing full-fledged conferences, and developing new ways to draw online communities together in person.

But as single-minded as their coverage is, verticals don’t have to go it alone. Expect to see more of them banding together in 2016 to share best practices, find efficiencies when it comes to common needs like technology and operations, and build distribution networks on emerging platforms.

Back to Indianapolis. Chalkbeat stayed on the stories that came out of that school board election, and went deep on issues affecting English-language learners in public schools. The audience for this insider coverage wasn’t huge, but it did include lawmakers, who then doubled funding for the programs that had lost it. Meanwhile, the most accessible pieces appeared in the Indianapolis Star, reaching a wider audience. Expect to see more impact at scale in 2016.