I have published two titles on the Kindle, the novella, A Catch Me Tickle Me Gene as well as a collection of short stories. They were all originally Hubs.
I have learned a great deal about publishing by doing this. I was so impressed that I went ahead and self-puplished paperbacks and now they're available from the regular Amazon site as well.
Anyone can do it, and there is a market of readers eager to read new writing.