I’m sure many have seen the news that Apple tracks where you go. Actually, it’s not new and Apple aren’t tracking you – your iPhone knows where you are but doesn’t send out the data. A Bad Guy™ would still need to get their hands on your iPhone (Or PC/Mac, with a backup on) to get the data. And if they can gain access to either of those, well, they could just as easily install their own application that will track far more than just location – such as contacts, recent calls and SMSes.
Actually, it’s really not that hard to find out where someone is. If you’re worried about your location, put your phone in “Flight” mode, with the radios off. (This also disables the GPS, due to some slightly odd rules on running GPS receivers on flights)
When the mobile phone networks were built nobody really thought that hard about security. Rather than worrying about centralising everything, SMSes are sent directly from the sending mobile network’s SMS Centre direct to the Mobile Switching Centre (MSC) of the recipient – with one operators MSC typically covering an area the size of a city. This means an operator (In any country worldwide) has the ability to look up the MSC of a subscriber to send them the SMS. If you can figure out which MSC numbers serve which locations… Oops.
There are even companies which offer the lookups as a commercial service, as it can be useful for
spammersmarketing departments to know which phone numbers are still valid. And some have gone as far as openly offering the location information as well.