Your mobile phone is giving away your approximate location all day long.
This isn't exactly a secret: It has to share this data with your mobile provider constantly to provide better call quality and to route any emergency 911 calls straight to your location.
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It may be tough to put a price on one's location privacy, but here's something of which you can be sure: The mobile carriers are selling data about where you are at any time, without your consent, to third-parties for probably far less than you might be willing to pay to secure it. more