GPS tracking is a perfect development which can save your life. Lots of people find themselves in a danger sometimes, it can be a natural danger such as earhquake, a volcano eruption or something like that.
Sometimes a phone number can give you a stress. You do not know the owner of the number. But there are several services offering you to give lots of informations about the numbers.
Long time ago, people did not have a chance to recognize the identity of dialers when they called without answering. But with the help of developments in the technology, people had this chance. It was not a dream anymore and never would be.