President Obama made Internet waves usually reserved for cat memes on Wednesday, when he answered questions on Reddit. But Reddit isn’t just for Q&As with celebrities  like Louis C.K. and Neil deGrasse Tyson—it’s also becoming a launching pad for talented, unknown writers.

Last year, I quietly achieved super-lurker status on Reddit, when I discovered its NoSleep subreddit, a subsection of the site that features user generated spooky stories. Some claim to be true, some are proudly fictional—but more than a few are absolutely terrifying and mysterious. And the form of Reddit, the way it features an initial user post and then nested comments to which the original author can reply, can heighten the narrative: some authors pretend to update their story in real time, others interact realistically with their questioners. And Redditors can vote stories up and down, making it easy to find  the community’s favorites.

Now Redditor Dathan Auerbach (user name 1000vultures), has become NoSleep’s first break out author success. On August 12, Auerbach released the Kindle version of Penpal, an eBook that collects the 6 part horror novella he posted on Reddit over the last year. In the original posts, Auerback pretended to be relating a true story—and this faux-documentary approach made his tale of a young man slowly recalling horrifying events from his childhood even more powerful.

As an eBook, Penpal is already a bestseller on Amazon, where it’s garnered 60 user reviews, many of which mention first discovering the story on Reddit. For authors, this is a perfect example of the new ways they can find and satisfy an audience. Auerbach joined a forum devoted to people who liked his kind of stories, wrote an episodic narrative that smartly took advantage of the way Reddit works, and then, after tweaking and listening to his commenters and their encouragement,  produced an eBook that he already knew had an audience.

Reddittors are quickly becoming eBook authors. In June the site’s founder, Alexis Ohanian, released his own eBook, “Make Something People Love.” In it Ohanian writes that when working on the Web, “Anything you create actually has to be good.” That’s always been the requirement of being a great writer; now, forums like Reddit give authors a fairly sure-fire way of finding out if they’ve succeeded.