Facebook founder and CEO Mark Zuckerberg will testify twice before Congress this week as legislators are prepared to ask him why the information of more than 80 million Americans was improperly shared with a political research firm.

Zuckerberg accepted an invitation to sit before a joint hearing of the Senate Committee on the Judiciary and the Senate Commerce, Science, and Transportation Committee on Tuesday, and a House Energy and Commerce Committee hearing on Wednesday.

>>Cambridge Analytica: What you need to know about the firm, Facebook and your information

Zuckerberg will be answering questions about the abuse of user data by the political research firm Cambridge Analytica along with questions about Facebook's retention of data from its Messenger app and bulk harvesting of public profiles on the site.

Last week Facebook officials said “malicious actors” were responsible for security breaches that allow collection of data on most of the site’s 2 billion users.

Here’s what you need to know in advance of the hearings.

What time are the hearings:

Zuckerberg will testify before the Senate Judiciary and Commerce committees at 2:15 p.m. ET Tuesday.

He will be before the House Energy and Commerce Committee at 10 a.m. ET Wednesday.

How can I watch: 

Click here to watch Mark Zuckerberg's joint hearing before the Senate Judiciary and Commerce committees on Tuesday.

Go to YouTube or C-SPAN on Wednesday to watch Zuckerberg's hearing before the House Energy and Commerce Committee.

>>Cambridge Analytica data breach affected up to 87M Facebook users, company says

Why is he being called:

Zuckerberg was invited to testify before Congress after Facebook officials initially admitted last week that 50 million of its users had information “improperly shared” when a British psychologist “scraped” data from people who took an online “quiz” and provided personal information to a firm that used the information to profile potential voters.

A few days later, that number was amended as the company's chief technical officer, Mike Schroepfer, said that instead of 50 million people having their information improperly shared with the political research firm Cambridge Analytica, "In total, we believe the Facebook information of up to 87 million people — mostly in the U.S. — may have been improperly shared" with the company.
In addition to addressing concerns over the sharing of information, the company has faced questions about political ads and posts on the site prior to the 2016 presidential election.

Zuckerberg told reporters last week that he made a "huge mistake" in failing to make clear what Facebook's responsibility is to its users.
>>Facebook breach: Want to leave the social media giant? Here's how 

Who will be questioning him:

On Tuesday, Zuckerberg will be testifying at a joint hearing of the U.S. Senate Judiciary and Commerce committees. The members of those committees are:

Judiciary

Republican members

Chuck Grassley, Iowa, (chairman)

Orrin Hatch, Utah

Lindsey Graham, South Carolina

John Cornyn, Texas

Mike Lee, Utah

Ted Cruz, Texas

Ben Sasse, Nebraska

Jeff Flake, Arizona

Mike Crapo, Idaho

Thom Tillis, North Carolina

John Neely Kennedy, Louisiana

Democrat members

Dianne Feinstein, California, (ranking member)

Patrick Leahy, Vermont

Dick Durbin, Illinois

Sheldon Whitehouse, Rhode Island

Amy Klobuchar, Minnesota

Chris Coons, Delaware

Richard Blumenthal, Connecticut

Mazie Hirono, Hawaii

Kamala Harris, California

Cory Booker, New Jersey

Commerce

Republicans

John Thune, South Dakota, (chairman)

Roger Wicker, Mississippi

Roy Blunt, Missouri

Ted Cruz, Texas

Deb Fischer, Nebraska

Jerry Moran, Kansas

Dan Sullivan, Alaska

Dean Heller, Nevada

Jim Inhofe, Oklahoma

Mike Lee, Utah

Ron Johnson, Wisconsin

Shelley Moore Capito, West Virginia

Cory Gardner, Colorado

Todd Young, Indiana

Democrats

Bill Nelson, Florida, (ranking member)

Maria Cantwell, Washington

Amy Klobuchar, Minnesota

Richard Blumenthal, Connecticut

Brian Schatz, Hawaii

Ed Markey, Massachusetts

Tom Udall, New Mexico

Gary Peters, Michigan

Tammy Baldwin, Wisconsin

Tammy Duckworth, Illinois

Maggie Hassan, New Hampshire

Catherine Cortez Masto, Nevada

Jon Tester, Montana

>>Facebook alerts users if their data was compromised by Cambridge Analytica

On Wednesday, Zuckerberg will answer questions before the U.S. House Energy and Commerce Committee. The members of that committees are:

U.S. House Energy and Commerce Committee

Republicans

Greg Walden, Oregon (chairman)

Joe Barton, Texas

Fred Upton, Michigan

John Shimkus, Illinois

Tim Murphy, Pennsylvania

Michael C. Burgess, Texas

Marsha Blackburn, Tennessee

Steve Scalise, Louisiana

Bob Latta, Ohio

Cathy McMorris Rodgers, Washington

Gregg Harper, Mississippi

Leonard Lance, New Jersey

Brett Guthrie, Kentucky

Pete Olson, Texas

David McKinley, West Virginia

Adam Kinzinger, Illinois

Morgan Griffith, Virginia

Gus Bilirakis, Florida

Bill Johnson, Ohio

Billy Long, Missouri

Larry Bucshon, Indiana

Bill Flores, Texas

Susan Brooks, Indiana

Markwayne Mullin, Oklahoma

Richard Hudson, North Carolina

Chris Collins, New York

Kevin Cramer, North Dakota

Tim Walberg, Michigan

Mimi Walters, California

Ryan Costello, Pennsylvania

Buddy Carter, Georgia

Democrats

Frank Pallone, New Jersey, (ranking member)

Bobby Rush, Illinois

Anna Eshoo, California

Eliot Engel, New York

Gene Green, Texas

Diana DeGette, Colorado

Mike Doyle, Pennsylvania

Jan Schakowsky, Illinois

K. Butterfield, North Carolina

Doris Matsui, California

Kathy Castor, Florida

John Sarbanes, Maryland

Jerry McNerney, California

Peter Welch, Vermont

Ben Ray Luján, New Mexico

Paul Tonko, New York

Yvette Clarke, New York

Dave Loebsack, Iowa

Kurt Schrader, Oregon

Joseph P. Kennedy III, Massachusetts

Tony Cárdenas, California

Raul Ruiz, California

Scott Peters, California

Debbie Dingell, Michigan

What will they be talking about in the hearings: 

According to the House Energy and Commerce Committee website, the hearing will “shed light on Facebook’s use and protection of user data, and will help all Americans better understand what happens to their personal information online.”

The joint hearing between the Judiciary and Commerce committees hearing is titled, “The joint hearing before the Senate Judiciary and Commerce committees is titled: “Facebook, Social Media Privacy, and the Use and Abuse of Data.”

Blumentha had a more dire description of the hearing. "I think we're at a moment of reckoning. It's really high noon for Facebook and the tech industry,” Blumenthal said.

Zuckerberg will be asked how the personal information of 87 million Facebook users was mishandled, and what steps the company plans to take to try to avoid having users data “scraped.”

Another topic sure to be addressed is what Facebook needs to do to identify the source of political ads and control the spread of misinformation. Facebook announced last week that it will require buyers of political ads to verify their identity and location, and those who are unable to do so will be prohibited from running political ads on the platform.

“These steps by themselves won’t stop all people trying to game the system,” Zuckerberg said in a statement posted on Facebook. “But they will make it a lot harder for anyone to do what the Russians did during the 2016 election and use fake accounts and pages to run ads.”

Thune said in a statement that “More than any one issue, I’m interested in Mark Zuckerberg’s vision for the responsibility Facebook plans to take for what happens on its platform, how it will protect users’ data, and how it intends to proactively stop harmful conduct instead of being forced to respond to it months or years later.”

Markey told The Washington Post that he is looking for any "recourse for victims" following the revelation of the Cambridge Analytica data scrape.
Sen. Kennedy said on CBS' "Face the Nation" Sunday that he might be in favor of Congress regulating Facebook.

"I don't want to hurt Facebook. I don't want to regulate them half to death. But we have a problem. Our promised digital utopia has minefields in it ... . But my biggest worry with all of this is that the privacy issue and what I call the propagandist issue are both too big for Facebook to fix, and that's the frightening part," Kennedy said.

Here are others looking into Facebook’s operations:

Here’s a list of agencies and governments looking into Facebooks practices after the Cambridge Analytica scandal.

The Federal Trade Commission will look into whether Facebook was out of compliance with a 2011 agreement over privacy issues.

Thirty-seven states and territories have signed a letter asking Facebook to explain how they monitored the data app developers collected.

The European Union, the United Kingdom, Italy, India, Indonesia and Australia have all opened investigations into Facebook's operating practices.

>>Facebook tweaks security settings after privacy fallout

What has Facebook promised to do already:

In advance of his testimony this week, Zuckerberg announced several new measures to help protect the privacy of the companies 2 billion users.

Included in the new measures are requirements that people reveal their identities and verify who they are if they want to purchase ads.

To get verified, Zuckerberg wrote, “advertisers will need to confirm their identity and location. Any advertiser who doesn't pass will be prohibited from running political or issue ads.”

He went on to say that Facebook will “require people who manage large pages to be verified as well. This will make it much harder for people to run pages using fake accounts, or to grow virally and spread misinformation or divisive content that way.”

He also pledged to increase security on the site by adding employees to watch for questionable practices. “So all in, we now have about 15,000 people working on security and content review, and we’ll have more than 20,000 by the end of this year,” Zuckerberg said in a post last week.

Click here to see everything the company has proposed to do since news of the Cambridge Analytica breach was reported.