I dunno.
It’s hard to get concrete evidence of anything working, but here’s something that I think counts. In the last few months I didn’t do much promotion, due to various personal issues, although of course I did keep writing. Storm Chaser, which came out in June, 2011, sold no books online in the last quarter. None. Nada. Zero. Under the Roman numbering system, I’d have vanished.
A couple of weeks ago, Storm Chaser was featured on The Fussy Librarian (www.thefussylibrarian.com), which gives a daily list of books in various genres. (You’ll have to check on the requirements for getting on the list; I believe the criteria has changed.)
So far in January I’ve made three sales of Storm Chaser, a book that’s two and a half years old. That would be a three hundred percent increase over the month before, if I’d sold one the month before. So far as I know, the only difference is getting the book listed on one website.
So there you go. Getting the word out there works; you just rarely know when, or what, or often how. Nobody said it was easy.