I’ve recently been testing out Amazon’s Kindle Unlimited feature. Basically, you can keep as many books as you like from a catalog of over 800,000 titles. You pay a subscription fee of $9.99 per month, and you can download and keep any book you want. It reminds me of Netflix or Amazon Prime Video Service but for books. It would be nice if they gave this service free to all Prime members, but paying $9.99 a month isn’t terrible. The service also includes a large catalog of audio books.
The way it differs from Amazon’s library feature, as far as I can tell, is that instead of being limited to checking out one book per month, you have access to read as many books in a month as long as they are in the Unlimited catalog.