I think it's a great idea that should have been done long ago. I don't have a mailing list, so this might be a suitable substitute. I intend to add a "follow me on Amazon" link in the back matter of my stories.
I'm following myself, so I'll report the results next time I upload something. I've heard it can take a few days after publishing before Amazon sends out the email to an author's followers. We'll see, I guess.
Anyway, I'm enthusiastic about it. :)