Described is a communication system including mobile communication devices. In the described system, the mobile devices may be wrist-worn watches such as are in common use today, except that the watches are specially configured to receive data in a “broadcast” mode and transmit and/or receive data in a “localcast” mode. The localcast mode includes the ability to transmit and receive data in a peer-to-peer fashion, allowing mobile devices to communicate directly with each other. The ability to combine two of these communication modes in a small, integrated and hence inexpensive and low-power package provides many advantages over existing personal communication device solutions.