Last August, I remember covering the story for my podcast of Amazon Webservices' bid to compete with PayPal in the space online currencies with the launch of Amazon Payments, and thinking that if anyone had a shot at taking out the online payments giant, it would be Amazon (Pete's coverage here). That hasn't happened yet for Amazon's service that allows third parties selling items on Amazon's extended network to receive payments from buyers.
Much like Google's Checkout service, it looks destined to be little more than a redirect service only, and limited to stuff sold from within the company's selling network. As such, also like Google Checkout, it seems to have avoided the wide-spread adoption like PayPal has received.
Perhaps to try to combat the perception that Amazon Payments is not just a shopping cart system for stuff from the Amazon site, they've released a few widgets and upgrades that website owners can place on their site. The widgets seem to function just like a PayPal payment button, and come in three varieties: Static, Dynamic and Alternate Payment Method (which allows the user to choose between multiple payment types and Amazon Payments).
As such, I think Amazon is off to a good (albeit quite a slow) start with their tool, but will have to significantly work on the image of it being more than a shopping cart/eCommerce tool for it to compete seriously in the space of digital currency.