Experts explain: What information could be affected by Facebook data breach

Facebook's CEO Mark Zuckerberg is scheduled to give testimony in Washington DC Tuesday on what is being referred to as the largest data breach of its kind.

Last month news of the Cambridge Analytica data breach made headlines after it was determined the company violated its agreement with Facebook by sharing user information.

Monday, Facebook began notifying the 87 million users affected by the breach.

70 million of them are located in the US.

Cambridge Analytica's, third-party quiz app, This Is Your Digitial Life, is at the center of the breach.

“This was kind of an app that was being promoted during and around the election, and basically you could download this app, and then you could take this survey about different things, and then they would actually pay you,” Epicosity Social Media Coordinator Skyler Crabill said.

Senator Mike Rounds says third-party apps often sell people's information, but what happened in this situation took it to the extreme.

“They went beyond what they had legally indicated to people they would be doing with that data, and they sold it to outside organizations, who then resold it, and it was used to try to convince or try to manipulate the way people thought about the election process,” Senator Rounds said.

So what exactly is a third-party app?

Have you ever opened a website and it gave you the option to register for an account or sign in using Facebook?

KSFY News reporter Kelley Smith checked her Facebook apps that fell into this category.

There were 76.

“I’m sure you'll go on there and see an app, and you'll be like oh I downloaded that app for one month two years ago, but yet it's still pulling my information from Facebook,” Crabill said.

Facebook compiles a wealth of information about each user.

Crabill says people can go to their settings, click on ads, your information, and hit categories.

Facebook knows what kind of device people use to access the site and even has information about which political party it believes the user is part of.

“Your household, typically what your job is, it lumps you into different technology tiers as well, whether you're an early adapter or somebody that comes to it late,” he said.

What other information could be at risk in the data breach?

It's easy to find out.

Go to settings and scroll to the bottom of the general page.

There is a link to download a copy of all your Facebook data.

“You can request a zip file of everything that Facebook has on you and they will email you a zip file that has your pictures, your Facebook messenger, your posts everything from Instagram and What's App,” Crabill said.

Kelley Smith downloaded her Facebook data.

If you think your messages are private. Think again.

Facebook stored more than 11 hundred of her messenger threads.

They aren't listed in any order, but some of them date back to 2008.

It also included a 312 page break down of everything that has ever been posted to her Facebook timeline as well as pictures and videos

Many people have not received a notification yet explaining if their data was affected.

A representative from Facebook’s press office says if a person has been affected by the breach, they should receive a notification by the end of the day Tuesday.

Crabill says this situation serves as another reminder that information posted on social media is never truly private.