I hope Amazon is using this to take over last-mile delivery. That would be an amazing opportunity to roll out something like http://www.cargocap.com/ - though probably not in a typical US suburb.
In a somewhat denser city, doing last-mile delivery by something other than a people-killing, air- and noise-polluting truck just makes a whole lot of sense. I know it's far off but there are few companies other than Amazon that I would trust to pull it off.