Four self-published authors will have a total of seven novels on the New York Times ebook bestseller list this weekend, and the founder of self-publishing powerhouse Smashwords is predicting the number is only going to grow.

The highest-ranking self-published author on the 5 August NYT chart is Colleen Hoover, whose ebook Slammed ("A girl falls in love with a neighbour who enjoys slam poetry, but they encounter obstacles") comes in in eighth place, ahead of ebooks by established bestsellers James Patterson and Karin Slaughter. Hoover, who self-published Slammed seven months ago and has just signed a traditional book deal with Simon & Schuster, also has her second novel, Point of Retreat, in 18th place on the NYT chart.

RL Mathewson's romance novel Playing for Keeps ("When a woman stands up to her aggravating neighbour, romance ensues") is in 16th place, Lyla Sinclair's slice of erotica Training Tessa in 17th, and Bella Andre has three self-published romance novels in the chart: If You Were Mine in 22nd place, Can't Help Falling in Love in 23rd, and I Only Have Eyes for you in 24th. The 25-title chart is dominated, as it has been for much of the summer, by EL James's Fifty Shades of Grey trilogy – itself originally published as fan fiction.

"We knew this day was coming. Self-published ebook authors are landing on the New York Times bestseller list in a big way [and] lightning struck multiple times this week," said Mark Coker, founder of Smashwords – which worked with all four of the authors to publish or distribute their ebooks – on his blog.

"It's a big deal to see a single Smashwords author on the New York Times Bestseller list, let alone four in one week. A year ago, it was unheard of. A year from now, it'll be more commonplace."

"I think readers are more focused on a good story that they can enjoy instead of where the book was published," said Mathewson, of the self-published authors' success. "Thanks to the internet they can research books before committing time and money on them. Flashy advertisements really don't mean anything to most avid readers. They care more about reviews, ratings and recommendations than they do about ads telling them what to read."