I became a published author because of Smashwords. Until I discovered their site (and that was purely by chance, if I remember rightly) I'd had no luck travelling down the traditional publishing road. In fact, I hadn't made it out of my front door!
When I realised there were such things as indie authors, and I could publish and be damned without having to secure a contract, however measly, my writing life was turned upside down. I embraced Smashwords with all the enthusiasm of a new lover. I published my first novel, then my second, until all five were loose on the digital world.
Some time after I published my first novel via Smashwords, I found I could publish through Amazon. So I did. At this point my books were digitally available on Amazon, Barnes & Noble, iBooks (Apple), Scribd, Kobo, and a whole lot more, and I used Createspace for the print version.
Then KDP Select came to my attention, and I was seduced by the marketing. I enrolled first one and then all of my books in the scheme, and have since regretted it.
The problem I have with Select (and with Amazon as a whole) is the growing lack of diversity within the self-publishing business. With Oyster closing there is one less outlet for indie authors. How many more will go before Amazon is the only child left in the park with a ball? If indies want to play they may eventually have only one option - do it the Amazon way, or don't do it at all.
Don't get me wrong - I publish on Amazon and am grateful for it. But what happens if /when the option for indies shrinks to only Amazon?
Authors, as a profession, need to encourage diversification, not repress it. And we also need to make sure that a single publisher doesn't become the only publisher, or we might find we are suffering the consequences.