Trip Adler, CEO of Scribd believes the entrant of a new competitor will be good for ebook subscription services as a whole:
The apparent entrance of Amazon into subscription market is exciting for the industry as a whole. It's validation that we've built something great here at Scribd. Publishers, authors and readers alike have all seen the benefit, so its no surprise they'd want to test the waters. Successful companies don't fear competition, but rather embrace it, learn from it and use it to continue to fuel their own innovation which is exactly what we intend to continue doing.
Oyster CEO Eric Stromberg agrees:
We’re not surprised. They have pivoted from transactional to subscription-based in other media, and have had limited success. They really paved the way in ebooks, and it’s exciting to see them embrace the market we created as the future of books.
Based on the leaked details, Kindle Unlimited is expected to cost $9.99 a month and offer a 600,000 title strong catalog when it launches. No one when exactly that will happen, but I am expecting that the service will go live in August or September.
Here's Amazon's promotional video for Kindle Unlimited, which as you can see suggests that KU will be available on the iPad, Android devices, and Amazon's own Kindle Fire Android tablets.
When the service launches it is going to cause an upheaval in this nascent market.
While some companies like 24Symbols have been providing a subscription ebook service for years (Safari Books Online has been around for over a decade) the market really only took off last Fall with the launch of Oyster and Scribd. They had the market to themselves for nearly a year, but soon these two established players are going to find themselves in the same position as Amazon's other ebook competitors: fighting it out for second place.
Of the two, I would say Scribd is better positioned to play second fiddle to Amazon. With 400,000 titles in their catalog, Scribd has a smaller selection but they also are available internationally. Oyster, on the other hand, is still only available in the US, so even though it offers a catalog with 500,000 titles it is still at a distinct disadvantage.
Also, Scribd got into this market after building a business in online storage. That gave them a head start in developing the tech and the engineering skill needed to compete in this market on an equal footing with Amazon. Oyster, on the other hand, launched with only an iPhone app and belatedly added an iPad app and (much later) an Android app.
But to be honest, it is really too early to say who will come in second to Kindle Unlimited; there's still time for Oyster to take its service international and work to catch up to Scribd.