If your phone is turned on and has signal, it can be communicating — whether you’ve asked it to or not — with a wide variety of companies, many of which you won’t have any direct relationship with.

And yes, this can happen even when you’re not using it.

Your phone and other personal computing devices know an awful lot about you. They know — and often share — things like where you are and where you’re going, who you’re friends with, what apps you use, which websites you visit and how often you visit them, who you email and call — the list goes on …

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