What is the purpose of Unlocking?

[bigtyme535]

I have a 3650 with T-mobile as my service provider and I'm trying to maximize the capability of my phone. Can someone please tell me the purpose of unlocking the phone or direct me to a good FAQ page on the subject?

[crashynot]

I have a 3650 with T-mobile as my service provider and I'm trying to maximize the capability of my phone. Can someone please tell me the purpose of unlocking the phone or direct me to a good FAQ page on the subject?
the purpose of unlocking the phone is that you will beable to use other provider SIM CARDS in your fone
and that you can use your fone in other contrys too with out haveing to use romeing

that is basicly it
nouthing else