When you download a phone app, there are a lot of terms and conditions you agree to before using it.
Do you read them or just click 'yes' and move on?
Isabel Brown, with the Public Interest Research Group, or PIRG, says it's become a very important question.
She says in many cases, Facebook, Instagram, Twitter, and YouTube know much more than you make public.
"You think the only information you're giving out is exactly what you post. But in reality, all of the info about the websites you look at, click on and different suggested content also goes into building this profile about you," Brown says.
She says when she looked into app privacy, she found Instagram knew more about her than what she'd posted.
And she says what she found about Facebook tracking has her concerned.
"They had a laundry list of other websites that I had opened on my computer. Some had nothing to do with Facebook," she says.
Brown knew the way these free apps make money is by selling your personal information but she says the extent is troubling.
And many times, users don't realize they agreed to let it happen.
So, PIRG put out a detailed instruction guide on how to protect your privacy using popular apps.
One example is how to make your Instagram account private by going to settings and then to "privacy account."
Brown says apps may make agreeing to something sound positive, like sharing your contracts will "help you find friends."
"It may not be as obvious clicking yes gives the app access to all the email addresses, phone numbers everything in your contact list," she says.
To remain as private as possible, Brown says to read all the fine print and set privacy settings from the beginning.
Brown says the apps can even be tracking you when you're not using them.
"Apps may not need that much info and users should feel empowered to restrict that access," Brown says.
Click here for PIRG's detailed instructions to protect privacy on your phone.
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