it sends a gps location on blackberry maps, like a pin point not the actual address. You have to be able to use the gps feature for this. So if you can't use gps then it wont work. All bb have this option in bbm
Yes it will not send it to everyone on bbm just the person your chatting with. blackberry maps is just what it sounds like you can open it up and it will show you your location and follow you where every you go on you device.
Pops right up in the chat then if they click on it, it will take them to blackberry maps. If you dont mind advice you should add yourself to bbm and you can check these things out on yourself before exposing it to someone.