Each November for the past 18 years, thousands of writers have taken the National Novel Writing Month (NaNoWriMo) challenge: each attempts to create a draft of a 50,000-word novel in 30 days. With word-counting apps, participation badges, writing prompts, pep talks, and in-person events, the NaNoWriMo nonprofit helps aspiring writers meet this goal. This year, executive director Grant Faulkner expects up to 350,000 aspiring writers to join the writing marathon—eventually adding to the tally of traditionally published books that were conceived during this hectic month of writing.

“We’re a tiny nonprofit, so we can’t truly track all of the NaNoWriMo novels that have been published­—so, we rely on authors to tell us,” said Faulkner, who took his post at the organization in 2012. When NaNoWriMo projects get published, participants report them using a form on the site. The nonprofit currently lists 449 traditionally published novels that began as NaNoWriMo projects. At least 80 of those books ended up at the Big Five publishers.

Faulkner thinks those figures are very conservative. “We’re bringing in a lot of outsider authors, and we’re allowing their voices to be heard in the world,” he said. NaNoWriMo has charted “astronomical” growth since 1999, when Chris Baty launched the movement with 21 other writers in the San Francisco Bay area. It continued to grow every year, becoming a 501(c)(3) nonprofit in 2005.

Each year, teams of volunteers around the globe guide participants through online forums and local gatherings. In 2016, more than 900 “municipal liaisons” organized events across six continents. The marathon also supports young writers in about 5,000 classrooms with workbooks and curriculum materials. The organization projects that up to 80,000 students and educators will also participate this November.

This outreach has created publishing networks in places where writers used to struggle to find support. “Authors live all over and frequently don’t have the same kind of in-person coworker community that someone with a more traditional job model might have,” said Kate Brauning, the senior editor at Entangled Publishing. Brauning has worked on two NaNoWriMo manuscripts from the author Julie Hammerle: Artificial Sweethearts and Approximately Yours. “NaNoWriMo helps to replace that writing community a little.”

“It’s been wonderful for the publishing industry,” said Laura Apperson, an editor at St. Martin’s Press. Three St. Martin’s novels began as NaNoWriMo projects: Lydia Netzer’s Shine Shine Shine, Rainbow Rowell’s Fangirl, and Nora Zelevansky’s Semi-Charmed Life.

Though Apperson hasn’t edited a NaNoWriMo manuscript, she has taken the novel-writing challenge five times. “If you have a community, you’re a lot more motivated to write; you’re a lot more motivated to start shopping your book around,” she said, explaining how the writing marathon has influenced the industry.

Author Elia Winters has published six of her NaNoWriMo efforts, landing deals with Carina Press, Harlequin, Pocket Books, and Samhain. She’s taken the challenge 17 times over the course of her writing life, but it wasn’t until her 10th marathon that her work found representation: Saritza Hernandez, the senior literary agent at the Corvisiero Literary Agency. “People who stick with NaNoWriMo year after year are going to get better at their craft,” Winters said. “If you’re only dribbling and drabbling your words and take 10 years to finish a single book, you might never be able to traditionally publish.”

Eric Smith, an author and PS Literary associate agent, counts a few NaNoWriMo participants as clients. “I appreciate the fact that NaNoWriMo gives writers a challenge to get the story out,” he said. “Writers can get hung up on the idea that one day they’ll write these books. This is a kick in the pants.”

One agent saw her established authors making use of NaNoWriMo’s adrenaline-inducing effects. “If they have something under contract, a lot of my already-published authors will arrange their schedules so they are doing NaNoWriMo as their first full draft,” said Kristin Nelson, founder of the Nelson Literary Agency. Her client Hugh Howey wrote early drafts of Wool and Sand during NaNoWriMo. Ally Carter, another client, quit her day job and drafted Don’t Judge a Girl by Her Cover during the writing marathon.

Aspiring author Scott Reintgen wrote a 61,000-word novel draft during NaNoWriMo, but it ended up getting rejected 53 times. Even though he couldn’t find representation for that first manuscript, he kept writing. Reintgen, who is now represented by Nelson, published his debut novel Nyxia with Crown Books for Young Readers in September.

“You’re building muscles and you’re leveling up and you’re getting better with every single word you put on the page,” Reintgen said. “That’s what being a writer is all about,” he added, reaffirming that NaNoWriMo models one of publishing’s fundamental virtues: endurance.