If there was any lingering questions around whether there is a market for monthly ebook subcriptions, Amazon surely went some way towards answering them when it introduced its $9.99 ‘all-you-can-read’ Kindle Unlimited plan last week. While this raised many concerns around the implications for authors’ monetization, it will also have piqued the interest of existing players in the field – one of which is Oyster, the oft-called Netflix for ebooks. While Amazon’s monthly subscription serves up 600,000 ebooks for $9.99, Oyster delivers 500,000 books for $9.95 a month. However, it’s reported that the vast majority of the titles available on Kindle Unlimited consist of self-published books via Kindle Direct Publishing, so these numbers may not tell the true story. But there’s plenty of scope for Amazon to flex its muscles on this front and expand its content significantly.