Since Making Peace with Autism came out six weeks ago, my wife and I have become addicted to Amazon sales stats. We got into the habit of reloading the Amazon page to see how the book was doing (nicely, thank you). Then I wrote an Amazon web services script to pull stats for a number of books.
Now I've created WHOA: the Writer's Homepage for Obsessing about Amazon. It's a customizable page that lists stats for the books you want to see. Try it out, or read About WHOA.
The list of books is all in the URL, so once you have a page you like, you can bookmark it to obsess over and over again. Or you can create a list and share it. For example, here's a Franken vs Limbaugh and O'Reilly smackdown.