This is a great article regarding PROMOTION of your books if you are an eBook Author... or a digital publisher. Of course, it mentions standard publishing as well, but more importantly, it lets digitally published authors know what they need to do to make money from their books. http://kriswrites.com/2011/04/06/the-business-rusch-promotion/
If you're not interested in reading the entire article, let me summarize. The bottom line regarding promotion for your digital books is.... publishing more books. Because it seems that the absolutely best way to get your book(s) noticed is WORD OF MOUTH. And who likes to talk more than readers who love to read... right?
Of course, you still have to have a web presence... because what good is word of mouth going to do for you if no one can find you online? And most of my own authors will be very happy to hear that it's not so much joining the social networks that is important as much as it is HAVING YOUR OWN WEBSITE. Of course, you should link your website to your publisher's website, as well as to the top places where your book (s) is/are listed, but the main idea is to make sure that if someone hears your name and wants to learn about you, that they can easily find you by typing in your name on their iPad or iPhone.
The article also mentions that the more books you publish, whether it's in one genre or many, the better, as that only increases the chances of word of mouth. Gone are the days of publishing when you make it or break it in the first 3-6 months. Which is a good thing for authors, since they could potentially start making money at any time... and continue making sales indefinately!
So the bottom, bottom line for authors who are digitally published is.... BE PATIENT.... CREATE YOUR OWN WEBSITE... and KEEP ON WRITING/PUBLISHING. Now that doesn't sound so hard, right?
And for those digital publishers out there.... don't be so quick to drop your backlist!