You may have noticed a bunch of news stories indicating Mark Zuckerberg was testifying in front of congress today about privacy on Facebook.

What’s all this about and should I be worried?

Like most big news today, the Facebook privacy ‘scandal’ is tied back to politics. But you should care about this story whatever your politics are.

How was my privacy violated?

When people say your privacy might have been violated, what they’re really talking about is whether or not items on your Facebook profile were shared. If you don’t do anything on Facebook that you don’t mind sharing with the world, you’re probably fine.

But let’s say you liked the Facebook page for Zoloft. That’s now part of your Facebook profile. If Facebook shared all your page likes with a third party (and you thought that info was private), you may feel your privacy was violated.

So when did this actually happen?

This week’s scandal ties back to a very specific case: According to Motherboard, a university researcher back in 2012 wondered if he could predict people’s “Big Five” personality traits based on their Facebook profile.

The researcher wrote a quiz for Facebook that asked you a bunch of questions to analyze your personality. When you took the quiz, you were asked to share a bunch of your ‘private’ data with the researcher.

HERE’S WHERE IT GETS MESSY: The way Facebook used to work, you weren’t just opting in to share your data, you were also opting in to share your FRIEND’S data.

ALSO IMPORTANT: Facebook no longer lets you share your friends' info. So some people might argue that the problem is ‘solved’.

Now, this researcher discovered you could learn a lot more than just Big Five personality traits. He claimed that by looking at an average of 68 Facebook likes, you had an 88% chance of predicting sexual orientation, 95% chance of guessing skin color, and an 85% chance of figuring out a person’s political party.

Another researcher at the university copied this technique and created his own quiz. He then sold all the data he collected to a company called Cambridge Analytica.

THEY BROKE THE RULES: Until the other researcher shared his data, he hadn’t broken any Facebook rules. You’re allowed to ask for this data from a user, but you can’t sell it to another company. As soon as the researcher sold his data set to CA, he was violating FB policy.

Was my data passed to Cambridge Analytic?

Facebook has created a tool to tell you if your data has been shared with CA. Keep in mind this means either (A) you took the specific quiz discussed above or (B) one of your friends did. Of course, there’s any number of other companies that may have been doing the same sort of data collection before Facebook changed their policy to prevent friend data sharing in 2014.

How worried should I be?

As I said above, you may or may not consider the data Facebook is sharing ‘private’. A lot of people realize that their Facebook likes may be visible to their friends (depending on how their privacy is set up). Personally, I’m not super worried--even though one of my friends DID share my data through the quick.

One last note: This morning it was disclosed that a highly limited number of people (about 1500) also shared their private inbox with the quiz developers. This story just broke--so it’s still developing...