Don't get me wrong, I love the idea of making access to reading material cheaper and easier. I think that might encourage people to read more, and that will never be a bad thing.
What bothers me is I've found no discussion or data about how this will affect authors' royalties. If self-pub is not available on Kindle Unlimited, how will that affect how Amazon pushes our books? Will there be no change or will they give preferential treatment to their new program? I have so many questions.
As a Kindle-published author, I have received no email from Amazon explaining anything about this program other than that it exists. That does not fill me with confidence that they're going to hand self-pub authors anything but the shaft.
OTOH, it could be an amazing entry to authors' work, which could lead to great prosperity for everyone. I'd just like to know how. That doesn't seem too much to ask.
===== UPDATE =====
I was wrong: There WAS an email that I somehow missed. Here it is for any interested party's edification.
Today we are excited to introduce Kindle Unlimited—a new subscription service for readers in the U.S. and a new revenue opportunity for authors enrolled in KDP Select. With Kindle Unlimited, customers will be able to read as many book as they want from a library of over 600,000 titles. KDP authors and publishers who enroll their books with U.S. rights in KDP Select are automatically enrolled in Kindle Unlimited. Inclusion in Kindle Unlimited can help drive discovery of your book, and when your book is accessed and read past 10% you will earn a share of the KDP Select global fund. For the month of July we have added $800,000 to the KDP Select global fund bringing the total to $2 million.KDP Select is an optional program that makes your book exclusive to Kindle and eligible for the following benefits:
Reach more readers – With each 90-day enrollment period, your book will appear in Kindle Unlimited in the U.S. and the Kindle Owners' Lending Library (KOLL) in the U.S, U.K., Germany, France, and Japan which can help readers discover your book.
Earn more money – When your book is selected and read past 10% from Kindle Unlimited or borrowed from KOLL, you'll earn your share of the monthly KDP Select Global Fund. You can also earn a 70% royalty for sales to customers in Japan, Brazil, India, and Mexico.
Maximize your sales potential – Choose from two promotional tools including: Kindle Countdown Deals, time-bound promotional discounts for your book, available on Amazon.com and Amazon.co.uk, while earning royalties; or Free Book Promotion, where readers can get your book free for a limited time.
Learn more about KDP Select and Kindle Unlimited. Visit your Bookshelf to enroll your titles in KDP Select, and click on "Manage Benefits" to get started.
Best regards, The Kindle Direct Publishing Team