A year after its launch, Oyster, an e-book subscription service that offers all-you-read access to trade book titles for $9.95 a month, has added tens of thousands of titles, including works from two of the Big Five, and expanded to all major digital platforms. Now Oyster appears to be attracting subscribers, and new publishing partners.

While Oyster wasn’t the first digital subscription service—specialized services by Safari Books online, F+W and several children’s services already existed—the e-book venture’s launch has focused trade book publishers on the subscription business model, and its potential for encouraging book discovery. Oyster’s launch was followed quickly by an announcement from Scribd and, more recently, the launch of Amazon’s Kindle Unlimited service.

“We see readers engaging our service and authors piggybacking on them. We’ve come a long way in the last year,” said Oyster CEO Eric Stromberg during a phone interview with PW. Stromberg read through Oyster’s stat sheet of accomplishments over the last year. The venture has grown from offering about 100,000 titles to offering more than 500,000 titles including adding tens of thousands of titles from HarperCollins, S&S and the Perseus Book Group over the last year.

Stromberg said Oyster offers access to more than 200,000 authors and titles from more than 1600 publishers. And after launching with support for only Apple devices, Oyster is now available on six digital platforms including all iOS devices, the web, mobile web reader and Android devices. The service provides a variety of technology and editorially driven recommendation services and has added new genre categories.

While he declined to give specific numbers, Stromberg said the numbers of Oyster subscribers is growing, “the past few months has seen strong subscriber growth driven by adding new digital platforms,” he said.

Indeed Stromberg said Oyster was generating “30% to 40%” growth in revenue each month for its top publishers. “There’s been tremendous growth in the trade book subscription market that didn’t exist before,” Stromberg said. “Now we’re one of the fastest growing parts of the book world.”

In addition, Stromberg said the service has been monitoring feedback from its subscribers on book discovery. “Our core mission is to help consumers find books they wouldn’t have found otherwise. At first people will go to Oyster to look for specific titles but over time that’s shifted to discovery through our recommendation services,” he said.

Oyster offers a variety of recommendations including offering listings of 46 genres, more than 1,200 titles lists, and editorial and algorithmic recommendations. On average, Stromberg said, Oyster subscribers are adding about 17 books to their reading lists, “while they’re reading something else.”