Apparently, the factory-installed OS X Lion is not the only novelty of MacBooks Air and Macs mini released today: AppleInsider, Apple quietly added support for Bluetooth 4.0 on all of these machines. In comparison, iMacs and MacBooks Pro launched in 2011 only feature Bluetooth 2.1 + EDR (Enhanced Data Rate).
Bluetooth 4.0 brings the protocols "Classic Bluetooth" (to offer compatibility with old equipment), "Bluetooth High Speed" (based on Wi-Fi technology) and "Bluetooth Low Energy". The latter, also called BLE, works in low latency and low consumption applications, at distances of almost 50 meters.
It is interesting to note that this sudden evolution (Ma simply decided to skip specification 3.0) came about a month after Apple joined the Bluetooth Special Interest Group. Now a solid bet, imagine that future iGadgets they will be compatible with such technology, perhaps even using it in place of RFID / NFC.