Let's be simple about this. I've selected the key articles out of this series which sum up the data I've found.
They are in reverse order (like a blog). If you want to follow along in a (more) logical sequence, read from the bottom up.
Essential points in summary:
1) You are on your own, as you always have been. Marketing has always been up to the author.
2) The steps for self-publishing success: a) Write a damned good book. b) Get it in front of as many eyeballs as possible. c) Get paid enough to make it worth your while, but give away more than it's "worth" to said buyer.
3) Always, always, always: "Follow Your Bliss."
I've just released the book which covers this (the reason for this research) and also have a parody "bookend" that goes along with it (free download):