The Kindle Singles store, according to its editor David Blum, is “like a bookstore where the manager also edits the books.” Blum is that manager-editor, and under his guidance the store has grown to feature nearly 400 works since launching in January 2011. When the store went live, its mission was to publish the kind of long-form journalism that has become harder to find as more magazines have shuttered and those still standing allocate fewer pages to in-depth pieces. Since the Singles program started, it has gained enough respect to attract major names—among the many heavy hitters who’ve released Singles are Christopher Hitchens and Stephen King—and to delve into fiction.

Blum, a veteran of alternative weeklies—he worked at both the Village Voice and the New York Press, during the papers’ headier days—has gained a fair amount of attention since the store took off. In an April profile in the New York Times, Leslie Kaufman wrote that he has “transformed himself from doctor of the dying to midwife of the up-and-coming,” becoming “a man whom authors want to court.” Certainly Blum has had a key role in raising the profile of the store. Telling PW that Amazon hired him “with a concept, but no content,” he said the directive from the beginning was open-ended: find “compelling ideas.” Now, with “a couple” of other editors on staff in New York, and Singles stores opening in both the U.K. and Germany (which will each be overseen by one editor), it’s fair to say that Kindle Singles has been a success. Last week, Amazon announced the launch of the Kindle Singles Interview series, featuring long-form interviews with popular figures.

Although Blum did go after some big names early on—he pitched Christopher Hitchens on doing a piece—he was, and remains, most drawn to discovering new talent. Established authors are the biggest sellers in the store—according to Amazon, the biggest-selling Kindle Single to date is Lee Child’s story, “Deep Down,” which has moved 285,000 copies—but unknown writers, most of whom published Singles when the store was relatively new, have been able to reach impressive sales.

Among lesser-known writers, one of the top sellers is a Columbia M.F.A., Mishka Shubaly. Between April 2011 and July 2012 he released four Singles—“Shipwrecked”; “The Long Run”; “Bachelor Number One”; and “Are You Lonesome Tonight?”—and, according to Amazon, Shubaly has sold more than 129,000 copies. With Amazon offering a 70% royalty on each Single, and each of Shubaly’s pieces priced at the popular Singles price point of $1.99, he has been making about $1.39 per copy. This means that, overall, Shubaly has made just under $180,000 from his four Singles. Given that an advance for the kind of work Shubaly has published—memoir-style nonfiction by an author without a platform—might fetch between $5,000 and $10,000 at a major trade house, the Singles numbers are impressive. (It should be noted that Singles authors have the option to publish exclusively with Amazon and, of the 394 Singles in the store, 212 are exclusives. Authors who do publish exclusively with Amazon get the benefit of inclusion in the Kindle Lending Library, where their work is free and they receive a royalty on each borrow. Shubaly, who has published all of his Singles exclusively through Amazon, estimated that he has made $40,000 from borrows alone.)

Shubaly’s first Single, “Shipwrecked,” about his being marooned on an island in the Caribbean, sold more than 6,700 copies its first week on sale, Shubaly said, adding that he didn’t have concrete reasons for the book’s success, but that Amazon, which promoted the title (as it does with all Singles) certainly helped. Among Amazon’s outreach was e-mail to customers alerting them to the title’s release. “But one e-mail from Amazon has the power to move continents,” he said. “I really didn’t believe it was real until I got my first check. Then I quit my job.”

As is the case with a number of other authors who have self-published, Shubaly has found that having a large body of work has helped bring in more money; put another way, backlist is key. “Each time I publish something new,” he said, “all the other titles get a boost.” Now Shubaly, who does not currently have a literary agent, plans to release another Single in September. As for the print world, he’s not so sure. “I would love to publish a paper book... but Amazon has spoiled me, so it would have to be the right deal.”

While the Singles store has grown in both size and cachet, Blum hasn’t changed his focus. Singles remain at 5,000–30,000 words and, although fiction is now an established part of the mix, he remains focused on nonfiction. (Blum estimated that the ratio of fiction to nonfiction in the store now is roughly one to three.) But with success Singles authors face more competition. Blum said he is now getting over 1,000 unsolicited submissions a month; to date he has published 45 Singles that have come in unsolicited. He said his publication schedule has remained largely the same, as he focuses on releasing between three and four new Singles every week.

Shubaly is not the only unknown to have made a surprising amount of money by publishing Singles. The question is whether he is an outlier. Now that the Singles store is populated by a growing roster of authors with major platforms, reaching bestseller status may be harder for those without immediate name recognition. Amazon believes the store is too new to draw any conclusions on long-term trends. Still, some wonder if lesser-knowns can truly compete with the bigger names.

Fred Stoller, a character actor who, during the Singles store’s early days, published a piece called “My Seinfeld Year” about a stint he spent writing for the sitcom Seinfeld, has sold more than 67,000 copies to date. Now, though, he doubts he could duplicate that success. “I’m fortunate I got in when I did,” he said over the phone from Los Angeles. “If I tried getting in now, and [readers] didn’t know me, I might not have the same luck. Andy Borowitz knocked [my Single] out of #1.”—Rachel Deahl