[jarofgreen]

IP address does not always personally identify someone without extra information, usually obtainable only with a court order. Your IP address does not move with you, your number does. IP can not be used to personally bother you at any point in the future. This also makes a mockery of any "safe mode" browsing you do, enabling you to be tracked regardless.

Also, just because this can be used for good does not mean A) it can't be used for bad B) it is sharing private data that should only happen with your knowledge and consent