There's some great discussion on here today!
Here's a couple more things that I believe may be related to indie success:
1. producing actual, physical books (to get word of mouth buzz going and give to book bloggers - plus it shows that you have confidence in your work.)
2. having a good short story, novel or collection free on smashwords and keeping it free.
3. don't scatter your force across a million different social media sites - do one or two really well for a substatial duration of time.
4. figure out who the key players are in your niche and be generous with them.