All my books are available at Amazon. And only at Amazon* or through Createspace (which is owned by Amazon).
Well, there's the ease. I'm lazy and Amazon makes everything easy for me. One place to sell books, one place to market books, one place to check stats... you get the picture. But that's not the only reason.
I've tried putting my books on other sites. Know what happened? Next to nothing. I sold 12 books total in 2016 through other venues. And by marketing through those other channels, I lost the ability to have my books in the Kindle Unlimited program. Compared to the 12 books sold in 2016 through other venues, people read (and I got paid for) the equivalent of 182 books. That's $9.47 elsewhere vs $382 in KU. The math doesn't lie.
Know what else happened? I got paid a fraction of what I would've made through Amazon on each book. Other venues paid me an average of 79c per book. Regular sales through Amazon on my $2.99 books is $2.04. Even with the KU per page money dropping, I'm still averaging $1.98 per book this year (down 12c from last year's average). I can't argue with the numbers.
But not everyone uses Amazon you say? I have considered the people who don't use Amazon. Really I have. Right now, those people who bought the 12 books last year may not be able to access my other books. (Well, they could if they used Kindle for PC or for Nook or for whatever device they have.) I'm truly sorry about that. And it makes me a little sad. I want everyone to be able to read my books, however they want to read them. Unfortunately, when I weigh their needs against the money I'd be losing, the answer is clear.
No money, no books. It's really as simple as that. It's why I've only published two books this year instead of the 3 or 4 in my other publishing years. Oh, I can still write books. I have scads of them on my hard drive. But until there is moolah in my bank account, I can't afford to edit them or put covers on them and make them available for people to read.
So, there it is. I'm Amazon exclusive and now you know why. Any questions?
(If you've downloaded my books from anyplace else in the past year or so, you've stolen them. And you're part of the reason why I can't afford to publish more books. Shame on you.)