“How successful are authors who self-publish their books as ebooks on Amazon?”
There are a number of self-published authors who are making a lot of money with their ebooks published on Amazon, and there is a number of them not selling.
This question, like many others, depends on who you are talking about. Many authors think that just posting their work for people to buy is enough to get the sales coming in. If they believe this, they are generally in for a rude awakening.
Those authors who are making good money from selling their ebooks do many things to get to that stage. They use social media or hire someone to do it. Many campaigns are run by them to get the name of their book into the public’s eye. Advertising on sites like GoodReads, Amazon, Google, FaceBook, Google +, Tumblr, Twitter, and many others needs to happen. These cost money, so the author’s income from sales will need to justify it.
Keep in mind that as sales increase on any given ebook, Amazon may increase the standings of it in their listing. If they see an increase in sales (usually in the hundreds to thousands) in any given week, they start boosting it by placing ads for it on the main page. They call this a hot seller, and due to the popularity of the work, believe boosting its exposure will generate exponentially more sales.
So, can you make a good living from selling a self-published ebook on Amazon? Yes, but it takes work. Lots and lots of work.