Image: Cell phone privacy © Jacqueline Veissid, Photodisc, Getty Images

Your cellphone is the enemy.

Sure, it connects you with people, the Internet, stupid games and even your bank account. But it's also a tracking device that your family, your favorite retailer and virtually any law-enforcement agency in the world can use to find you.

And you're complicit in helping them do so. By keeping your phone on, you are letting any number of people have access to private information about you that you might not think you're giving out.

Sometimes you're putting the information into pretty packages by signing into sites like Foursquare -- which is linked to your Facebook account -- when you enter a restaurant, a bar, even a church.

"Location information can reveal a great deal about a person," said Catherine Crump, a staff attorney at the American Civil Liberties Union.

It can show who you're friends with, what medical offices you visit, what organizations you belong to and, in worst-case situations, where you've been when you don't want to be found.

And, just like you see on the TV crime shows, the longer your cell phone is tracked, the more information about you is uncovered.

Consider the uproar around the controversial "Girls Around Me" app for iPhones that looked to some like a stalking tool. The developers, in a long-winded response to The Wall Street Journal in March, said the app was meant only "to make geo-social exploration of popular venues easy and visual."

It did so by using publicly available data from Foursquare and Facebook to tell users which bars and nightclubs, for example, were hot on a particular night.

It was billed as a go-to tool for guys looking for hot chicks who used Foursquare to see where they checked in on a given map area. In fact, the app would note anyone, male or female, who had checked in at places in the vicinity.

Not only would users know who was where but, through public information posted on Facebook pages, the users in some cases were able to find out a girl's name, what she looked like, her birthdate, where she went to school and worked, who she might be with and any number of things that people share through social media sites. What's more, the girls had no idea they were being tracked that way.

(After Foursquare cut off access to the app, the developer pulled it but said it would continue to tweak it and plans to reintroduce it.)

That underscores the conundrum with your cellphone: While it makes it convenient to find your friends, directions or the weather, you give up a little piece of your privacy each time you use it.

"Your cellphone is your best friend who is a tattletale," said Mike Gikas, a senior electronics editor at Consumer Reports. "It's there for you, it comforts you, it gets you stuff -- but then it tells the world about it. And the more you tell it, the more it's going to share," he added.

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Police track cellphones

Increasingly, law-enforcement agencies are using cellphones to track the bad guys, but catch a lot of good people like you in the crosshairs, according to an exhaustive study by the ACLU.

The ACLU asked 380 police departments nationwide about their policies and practices for cell-phone tracking, with and without a warrant. Of the 200 that responded, only 10% said they didn't use cell-phone tracking at all.

The report revealed that the majority practiced at least some form of cell-phone tracking, with many doing it "quite frequently."

The rationale, of course, is to ferret out criminals and terrorists by seeing where they go, to whom they talk and what they're texting without the sometimes time-consuming process of first securing a warrant.

GPS tracking by police is also extremely valuable in the case of a missing child, a potential suicide or strong belief that someone is facing immediate danger of death or serious injury.

Some police departments, like the Oklahoma City Police Department, are reluctant to go through the time and paperwork needed for a warrant when the "potential for disruption of law enforcement activities is high in the area of investigations," according to its correspondence with the ACLU. "The police department should not be required to reveal the means and methods of investigations in particular cases or in general."

While many people might not argue with that, law-enforcement officials aren't only tracking the one under suspicion, but whomever he talks to -- whether that's his mother or his pizza-delivery guy -- and their every move.

Cops might ignore where the pizza-delivery guy goes after work, but they still have the information on hand, a cause of great concern for privacy advocates such as the ACLU.

"If they collect the information and don't do anything with it, the risks are mitigated," ACLU's Crump said. "But you still have the risk of a huge amount of personal information sitting around and who knows what security provisions are in place."

She added: "That's not the sort of thing that law enforcement should be getting into without good reason to believe that searching will turn out evidence of wrongdoing."

Some agencies are not just tracking individuals, but communities of people. In what's called a "towering dump," law-enforcement agencies gather information from every person who was near a particular cell-phone tower at a given time.

"They may not be able to search someone's car without a warrant but if they can see the same thing by tracking someone's cellphone, what's the point," Crump said.

Meanwhile, your carrier is more than happy to help. Many carriers routinely respond to law-enforcement agencies with such requests -- and some charge them a hefty fee to boot, according to the ACLU report.

And there's no way to hide from them. "You always have a choice [to hide] with apps, but the phone company always knows where you are," said Consumer Reports' Gikas.

The laws could change, considering that the ACLU report comes on the heels of a January Supreme Court decision that said legal authorities overstepped their boundaries by attaching a GPS device to a person's car without a warrant. The action stepped on Fourth Amendment rights, which cover unreasonable searches and seizures.

The U.S. Court of Appeals is expected to hear a case this year on whether it's permissible for the government, including police departments, to access cell-phone data without a warrant.

The family plan

You don't have to be a cop to use cellphones to track peoples' movements. AT&T, for example, has the FamilyMap plan that, for a charge, lets you locate others on your service plan, as well as in the entire AT&T network coverage through A-GPS, which is assisted GPS tracking, or through cell-tower information.

There is also no shortage of cell-phone tracking devices, some legal and some on the edge. Just do a quick online search to see.

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"Technology brings a lot of convenience, but it also creates ample opportunities for abuse," Gikas said.

Short of turning your phone off or keeping it in airplane mode, which cuts off radio signals, there's not much you can do to be certain your cellphone isn't being tracked. Nonetheless, you should be aware of what you're opening yourself up to and take some precautions.

  • Read the fine print before you download an app. Gikas tells the story of a guy who was ready to download a weather app when he read that the site reserved the right to record keystrokes. It could have been a legitimate request to help improve keyboard functions, but it also could have been a bogus site.
  • Don't unify your accounts. The trend of using one password to automatically log you into other sites is open territory for intruders who breach corporate or website security walls.
  • Don't tie accounts together. There are a growing number of sites from Twitter to Pinterest that encourage you to sign on through your Facebook account. Doing that lets anyone on those other sites readily see whatever you've left "public" on Facebook.
  • Be careful about what information you give up to any site or company. Remember that companies sell information about you to marketers who are aggregating those bits and pieces for a bigger picture of who you are and what you might buy.
  • Check and recheck privacy settings on social-media sites. They can change without warning and with little notification efforts.
  • Contact your legislator about police using cell-phone tracking without warrants and updating electronic privacy laws that didn't consider the Internet and advanced technology when they were formed in the late 1980s.

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