It means that you are pre-wired for bluetooth, but the important parts are not there.
Most people (myself included) are going with a Parrot ck3000 bluetooth box and then an aftermarket steeringwheel control box (connect2 or aduicom) that allows your existing buttons to be used with the aftermarket bluetooth.
Used it with my blackberry & I love it.
http://forum.e46fanatics.com/showthread.php?t=720922