So far, I have many "to-reads", but the really important, "read and review" hasn't happened. I have not seen any bump in sales. So although I can say, "I'm building my brand," the real answer here is that this book isn't selling, and selling is fundamental.
This promotion will be done towards the end of July. I'll figure another promotion after that.
Annoyingly, any promotion (or at least the ones that I looked at) requires a discount of some sort. My tools for doing that are rather poor.