Apparently, according to a post at digital book world that's full of math and math-like ideas that lost me immediately, there's a way that Amazon figures out which books to push. When they stop pushing "People who bought this book also bought" or whatever, then you drop off the face of the earth which is exactly what happened to Not Low Maintenance at the beginning of the summer. Carolyn McCray assures us you can impact this by pricing changes.
Anything that starts to seem like work/a hassle is when I drop the idea. Which is why you don't find me on MyFace or Twitter. It was hard enough to learn Photoshop, that might have worn me out for the rest of my life. Pricing doesn't seem to make any difference in my experience except that I stopped getting drunk trolls reviews on the Kate book when I raised the price of that.
I think the big picture is that some people are selling really really well because they managed to tap into a vital readership. Other reading niches haven't arrived yet. I'd rather spend my time writing and waiting for more readers to show up than what is probably banging my head against a wall trying to find readers who haven't arrived in large numbers yet. Christmas will usher in a new set of readers so by January we'll have a good idea how much that rising tide raises our boats.