Every time you download an app, search for a website, send a text, take a picture of a QR code or drive past a store with your GPS on, your every move may be tracked by your cellphone company.

Marketing insider Mark Johnson says your data trail is worth big bucks to cellphone companies.

Many people have no idea this information is being collected, packaged with details about your age and gender, aggregated and sometimes sold to third parties.

"They know you were playing Angry Birds, they know that you drove by Sears, they know you drove by Dominos pizza, so they can take that and take a very unique algorithm that can focus on your behavior," said Johnson, president and CEO of Loyalty Marketers Association.

Smartphone user Harrine Freeman is so creeped out, she turns off her GPS when she drives and shops. She also clears her browser history.

"I think it's an invasion of privacy," she said. "I don't think cellphone companies should sell your information."

All the major cellphone carriers admit to collecting information.

Verizon acknowledges it aggregates the information and sells it to businesses without personally identifying users.

Some cellular companies say there's an advantage to tracking users. They say users get ads that are relevant and can save them money.

"This is something that consumers are automatically opted into," said Rainey Reitman of the Electronic Frontier Foundation.