Let's not forget this little gem
A patent application assigned to Ortsbo (filed August 2011), System and Method for Sharing Information Between Two or More Devices. The patent details a system for sharing digital information between devices in close proximity using a sound signal. Within this system a receiving device is notified by sound of a sharing device. The receiver then accepts the request and would receive the data from the sharing system. It is not stated what the information may be; however it does allow for encryption and limiting access to the data within a time frame or location.
The defining features of this patent are: the ability for the sender to limit the range over which s/he wishes to send the data; the ability to transfer data without an Internet connection, as it uses radio frequency transmission when Internet connection is not available; that it simplifies the process for up/down loading from cloud hosting services, which is uses to store the data.
https://doublewide1.blogspot.ca/2012/03/calm-before-storm-intertaiment-media.html