Bluetooth Low Energy (BLE) is primarily designed for devices which do not use much power. Examples of such devices are sensors, fitness and medical devics.
The basic principle of BLE is centered around attribute protocols (GATT).
The Bluetooth SIG defines a variety of GATT based profiles, services and characteristics (http://developer.bluetooth.org/gatt/Pages/default.aspx)
The Bluetooth API needs to be extended to cater for basic GATT and possibly more specialized profiles/services.