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Logging In Via Facebook? This Is All the Information You Could Be Transmitting

Alyssa Bereznak
National Correspondent, Technology
Yahoo Tech
Facebook Privacy

Social networks like Facebook, Twitter, Google+ and more all offer the ability to register accounts at other websites and apps using your login information from those sites. So, instead of creating 100 different accounts with every app you try, using your email address and a unique password, you can just log into all of them using Facebook or Twitter. 

It’s a convenient, generally secure system — though it does have some privacy trade-offs when compared with just using your email. 

Case in point: A British marketing start-up called Bakery London recently sent a reminder of just how much social networks know about you — and how much information you’re sharing through them — when you use one as your identity. The company recently tweeted a screenshot of all the information a brand receives about you when you log into its website via Facebook. Take a look:

Yup, not only can a company automatically log basics like your address, email and gender, but it may also know your current location, list of friends, relationship status, and other, more subjective, nuggets about you, too. And, hey, at a certain level, it can also track the likes, dislikes, and basic information of your friends.

To be fair, you’re usually warned that you’re signing away your right to these specific privacies when you agree to log into a site via Facebook (just look at the notice Gilt gave me below). No one is forcing you to accept those terms. You can just press Cancel and use your email address, or create a unique username. 

And not every company collects all that data. As Facebook notes, other apps ask for only the personal information necessary to providing you their services (which, I suppose, is in the eye of the beholder). So even if Gilt wants to know every one of my personal tics (to enhance my retail experience, naturally!), an app like Lyft asks only for my public profile, email and friends list. That being said, asking for a limited amount of people’s information is only a recommendation from Facebook, not a rule.

Bakery London also tweeted out screenshots of the personal information that other big companies are providing.

Here’s Twitter’s:

(A media rep from Twitter told Yahoo Tech he wasn’t familiar with this dashboard but said Twitter details all the information that’s offered via its public-facing APIs here.)

LinkedIn’s:

And lastly Google+’s:

A Google+ rep noted to us that developers can access only the personal information that users have decided to make public (which almost never includes a person’s address). It, too, has all the information available to outside apps online here.

So website registrant beware. Maybe it’s about time you revisited your Facebook privacy settings? 

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