I wonder too if many readers just don't think about reviewing. For a few years I just read the stories and it was not until I submitted by first story that I began to understand the whole review process. It wasn't that it wasn't clearly explained but that I just didn't take any notice of it.

I agree that watching the number of readers rise is fun, though you don't know if they read all the story or not. It is a curious thing, but so long as I get at least a few reviews, to let me know what they liked or didn't like about the story, that is good. That to me is the most important part about reviews, if I can get a feel for what worked or didn't work, I can use it to improve my next story.