Authonomy is a web site where writers can go to post part or all of a book they want to here published. Once posted, people on the site are expected to see and comment on the work. The best works are supported (backed is the site jargon) and rise in rankings. Writers are also ranked. The most you read and comment on the higher your personal ranking is.
The site is run by HarperCollins. Every month they take the top five books and review them. In some cases this leads to a publishing deal. Most often it doesn't. And in my experience, the entire site fails to achieve the promise set out by the publisher.
Initially I used the site on my first novel is get some feedback to see if I could get high enough in the rankings to warrant a review from the publisher. As it turned out, I couldn't get above 1000. Additionally, what I found was the site is more about wheeling and dealing, making bargains with others so that if they back your book, you back theirs.
So the more you play that game the better off you are. Ultimately I gave up on that because that's not how I want to spend my free time. I want to write not play politics.
So I don't recommend the site. It seems pointless. I've had better luck elsewhere.