Multipoint technology means that you can connect two phones to the Q1 at the same time and answer whichever one rings. For example if you have a business phone and a personal phone you can connect them both to the Q1 at the same time.
The BlueAnt Q1 supports "true" multipoint technology: although other headset makers claim to support multipoint, most other headsets in the market today actually disconnect the second phone when you are on a call on your headset. This means that if you receive a call on your other phone while you are already on a call you will have to answer that call using the phone handset.
With the BlueAnt Q1 both phones remain connected even when you are on a call. If you get a call on your other phone you can use the Q1 to put your active call on hold and answer your other phone (just hold down the "Vol +" button for one second).
If you want to put the second call on hold and swap back to the first call on the other phone, just hold down the "Vol +" button again. You can keep swapping between calls and phones as many times as you like.