Self-published authors have many reasons to self-publish, starting with the inability to interest an agent or a publisher in their work. Agents and publishers, of course, look at a manuscript as a product; it's something to sell. If they don't believe the product will sell, they won't represent it or publish it. The usual reasons they don't believe it will sell include: It's too much like something else on the market (or that we're about to publish). It's not like anything else on the market (so there's no market for it). It needs so much editing, it's not worth our investment to make it publishable (r.i.p. Maxwell Perkins). It doesn't appeal to me. There are a million reasons not to publish a book by an unknown author, very few reasons to publish.
Thanks to technological change, however, authors who could not find an agent or a publisher in the past and who had to lay out several thousand dollars and end up with a garage full of unsalable books—i.e., they went to a vanity publisher—can now publish their books for very little money, keep the books in print forever, and print one only when a reader orders it. Or, with an e-book, not print at all.
Self-publishing also means that authors have to do all the marketing grunt work themselves—finding reviewers and getting the word out about themselves and their books. I have learned that many bloggers who review self-published books will, if their reading list is overwhelming, agree to an e-mail interview, and I have been taking advantage of every opportunity offered.
I have now been interviewed by HamletHub, A Writing Primate, and more that have not yet been posted, as well as been reviewed by reviewers who have put them on the Amazon site. I am grateful for these opportunities to let the world know more about me and my books.