A very cool way to have your laptop notice that you (actually your bluetooth phone) is nearby or not, and keep your system secure depending on where you are.

Essentially you pair up the laptop and phone, the MAC address of the phone is known to the laptop and when you are near, it senses the phone and lets you access the machine, but when you walk away (always a BAD idea to leave any laptop alone and logged in, right OPS Team???) it blocks access to the machine.

Article here.



P.S.  Thanks to Peter S. for this link.