Skoobe was something of a surprise when it launched 19 months ago. It is a joint venture between Bertelsmann and Holtzbrinck (2 publishing and media conglomerates that own Random Penguin Solutions and Macmillan here in the US, respectively). Neither of the US publishers like library ebooks, so I was surprised to see their parent companies experimenting with a Netflix-style plan.
This service currently offers 25,000 titles which can be read in Skoobe's Android and iOS apps. I don't know how many subscribers Skoobe has, but according to Google Play somewhere between 100,000 and half a million apps are in use by subscribers (who are paying 10 to 20 euros per month).
At the lower end readers have the option of downloading up to 3 titles on 2 devices, while premium subscribers can download up to 15 titles at once and keep them offline for up to a month. Subscribers to the basic service have to go online everyday to re-validate the files.
Skoobe is currently only available in Germany, but the website hints at the possibility of international expansion. Given the current limited content and ridiculous technical limitations, I can honestly say that I don't care if that ever happens.