In 2010 Amazon sold more Kindle books than hardcover books. The following year Amazon sold more Kindle books than paperback and hardcover combined.
The single biggest advantage offered by having an e-book on the Amazon Kindle is that your Kindle e-books will never go out of print, so they will keep on selling forever. Printed books, on the other hand, have a very short life on bookstore shelves.
Reddit.com user "throwaway_writer" wrote about his first $1000 day as a Kindle author:
http://www.reddit.com/r/writing/comm...he_first_time/
It didn’t happen overnight: his journey from $0 a day to $1000 a day took 8 months.
At the time the thread was written he had 80 titles for sale for the Kindle mostly as short stories, compilations of the short stories and novellas. That was in late 2011, his title count now is 200+.
His titles are in multiple genres including kids titles, non-fiction, science fiction and erotic romance.
He uses a different pen name for each genre.
He says sales come from 5 things: Cover, Description, Ranking, Title, Reference. Notice that he does not list "content".
He says Kindle book buyers make their buy/don't buy decisions in a manner of seconds. Therefore....
He believes a good cover, great blurb (short, to-the-point, keyword friendly description of your book that convinces the reader to buy, and a solid linking strategy is more important than great content.
He does ZERO promotion. No blog posts, no Facebook account, no Twitter account. Instead he lists each book in 2 categories and adds a clickable link to his first book in each succeeding book.
Now get this: the link is his own affiliate link. Thus he makes a small sales commission on top of the 70% "cut" Amazon pays him as the author. I LOVE the way this guy thinks!