For instance, recent news reports that 60 million Spanish phone calls were monitored by the US National Security Agency in just one month. I have no idea why they needed information about people overseas. But that's the nature of spying nowadays. When this super-sized snooping operation is challenged, its protectors claim the information collected is harmless.
In a criminal's possession, a database containing seemingly innocent metadata (data about data) could be used for blackmail. That is, if the person had something to hide. The say everyone has secrets—a lover, a business deal, a theft, or a political alliance.
In fact, analyzing a person's communications can reveal their whole social network. People on intimate terms are more likely to contact each other late in the evening. When those calls cease, perhaps the relationship has ended. On the other hand, if the database records only one call to a specific number every year, they are unlikely to be close to the person at that number. Similarly, a string of phone calls could reveal a story. If a young woman calls her mother, then her doctor, followed by the man she has spoken to every day for the last three months, and then an abortion helpline, those conversations divulge what is going on.
Why would a spy want to know these things about our personal lives? We've all seen movies about use of information to trap someone before blackmailing them or using the lever to entice them to commit a crime. People in stories who know about these things use toss-away mobile phones. To my mind, it would be simpler to leave the device at home. But that's the antithesis of what the mobile phone is about. You wouldn't be able to contact anyone or receive important calls.
I don't own a mobile phone. I'm not young enough to have been convinced of their importance. My husband always forgets to take his with him when he leaves the house. Not that he misses anything. Gone are the days when someone needed us.
No matter which way you look at it—up into space in the direction of hovering satellites or along a busy street followed by surveillance cameras, the web of technology entraps us in any society.