Discussion: A Netflix type service for books?

A little while ago, this article (which is very short, so feel free to read it) was sent to me. I thought the idea was really interesting. While the idea of a “Netflix for books” on Amazon does seem like speculation right now, it might just be a matter of time until someone big grabs it and runs with it. Basically, an individual would pay a fee to have unlimited access to a ton of books. If the person running with that idea was Amazon and Kindle, the impact it might have on those of us who use digital reading devices might be rather profound. Then again, it might not. 
What do you think of this idea of a “Netflix for books”? Do you think, if Amazon did do something like this, it would effect the book world dramatically? Would you use that service? Any other thoughts?