Why was Book Subscription Service, Oyster, closed down?

News that Scribd has hit 1 million paid subscribers, and an annual revenue rate of $100 million a year, brings up some very interesting questions If Scribd is making $100 million a year, and has 1 million paid subscribers, how much is Kindle Unlimited making?  Our post on How Big is Kindle Unlimited? will address this in the near future Why did Google buy and shut down Oyster, the Book...