Check out this post from the How to eBook blog on what motivates authors to promote their books
What will influence authors as to whether they will promote their books to the news media?
It’s not a trick question. The author of the 21st century must be very active in promoting one’s book and brand. If the author gets help from a book publisher – if a publisher’s involved — an author will still heed to supplement its efforts. No one can do everything that is necessary to properly promote and market a book. It takes a village.