I just noticed yesterday and was so pleased to see it, though I don't have a Kindle or any sort of e-reader myself. I really just like paper books. Of course, the Kindle is probably like the iPhone or a dirt rake...one of those things I was like: I don't need that. What on earth would I do with it? Only to get one and wonder how I ever lived without it (okay, that's a serious exaggeration where the dirt rake is concerned)
Anyway, you can now read The Mark on your Kindle (go ahead! right now! read it!) and maybe someday I will, too.