Tony asks my view on pplkpr.
pplkpr is an app that tracks, analyzes, and auto-manages your relationships. Using a smartwatch, pplkpr monitors your physical and emotional response to the people around you, and optimizes your social life accordingly.
Well at least its not a complete system, it works with other wearable devices.
pplkpr has been extensively tested with the Mio wristband, but any Bluetooth LE (also called Bluetooth Smart or Bluetooth 4.0) device that transmits heart rate in real time will work. This includes the Polar H7 chest band and the Zephyr HxM.