http://www.techradar.com/news/amazon-key-explained-why-the-online-retailer-wants-to-get-its-foot-in-your-front-door

Would you let a stranger into your house while you're out just to drop off a package? Amazon thinks you will if the tech is right, and is launching Amazon Key on November 8 in 37 cities in the US. 

However, the service – which will allows couriers to open your front door and drop-off a package – is less about your convenience, and more about Amazon’s ultimate ambition; it wants to own the smart home future. But is it safe?