I just bought a book
on amazon.com and got it delievered to my PW, and on the confirmation screen
on amazon.com, I now am being offered to add the Audible edition with one click (no more logging in to Audible and completing the purchase)
and to have the purchased ebook delivered to an additional device!
That's why I love Amazon - they don't just stop at great user experience, they are constantly improving it!
Now if only they could add some type of organizational tools for ebooks in the Manage my Kindle interface....