Apart from all the other issues mentioned in this thread, one of the issues that stymies products like this is the asymmetric nature of delivery networks. From

Apart from all the other issues mentioned in this thread, one of the issues that stymies products like this is the asymmetric nature of delivery networks. From a user experience perspective, it's a lot easier to deliver something TO a person's house than it is to deliver something FROM a person's house. After your first attempt trying to return a tool, you become discouraged from ever trying again. But you know what, we actually have a highly efficient system for transporting packages from people's houses, it's called the trash and recycling network. I wonder if there's an opportunity there to leverage this network... Imagine if returning something was as easy as wrapping it in a special plastic bag and then throwing it in your recycle bin. On the truck, special sensors would detect the presence of the bag and shunt it to a separate storage area of the truck and, from the depot, it would be placed in the conventional mail stream and sent to where it needed to be. Probably crazy unworkable but fun to think about :).