Facebook CEO Mark Zuckerberg will face Congress in two separate hearings this week, as his company grapples with intense scrutiny over privacy and security on the social media site. It will be Zuckerberg's first appearance on Capitol Hill.

On Tuesday afternoon, more than 40 senators will crowd into a hearing room, where members of the Senate judiciary and commerce committees will have four minutes each to question Zuckerberg. A similar scene will play out Wednesday, when he is set to appear before members of House Energy and Commerce Committee.

Both hearings are expected to be lengthy spectacles following in the long tradition of widely televised congressional inquisitions into corporate scandals — like the 1994 testimony of tobacco CEOs, the probe into steroids in baseball in 2005 and the interrogation of banking executives after the 2008 economic crash.

Here are five points to know to before the Facebook hearings get underway.

1. Congress wants answers on what Facebook really knew about Cambridge Analytica

The high-profile hearing was announced in response to widespread public outcry over the news that the private information of some 87 million users was shared with a political data firm, Cambridge Analytica, in violation of Facebook's policies. The information was gathered though an app created in 2013 that invited people to take a personality quiz, while also collecting some data from friends of the quiz takers.

The data breach took a political turn because Cambridge Analytica, a British firm, has ties to former White House adviser Steve Bannon and Republican megadonor Robert Mercer. The firm played a role in the 2016 presidential election, first working with Sen. Ted Cruz, R-Texas, and then with the Trump campaign. A source close to the Trump operation says psychological profiling was not part of that effort. Cambridge Analytica released a statement on its website on Monday denying the company provided any "polling, data analytics and digital marketing for the Trump campaign."

Democrats in particular want to know whether the firm exploited users' private information to influence the outcome of the presidential election.

Facebook now says it had stopped these kind of data grabs back in 2014, but news reports suggest Cambridge Analytica did not destroy the information as it had certified to Facebook. Facebook officially started on Monday notifying people whose profiles might have been part of the Cambridge Analytica data grab.

Facebook has also suspended another data analytics firm, Cubeyou, over allegations of improperly collecting people's data through quizzes, according to CNBC. Cubeyou denies wrongdoing.

Some lawmakers, including Virginia Sen. Mark Warner, the top Democrat on the Select Committee on Intelligence, raised questions about Cambridge Analytica in the past and say they are frustrated that Facebook dismissed their concerns.

"I don't think Facebook has been fully forthcoming," Warner said on NBC's Meet The Press. "I called out Facebook back in December of '16. In the spring of '17, I questioned microtargeting and the use of this really sketchy firm Cambridge Analytica. Early on, for most of 2017, they blew that off."

Now lawmakers want answers directly from Zuckerberg about what he knew and did not know about how firms like Cambridge were using and accessing user data.

2. Congress wants to make a public show of grilling Zuckerberg ...

The hearings on Tuesday and Wednesday are expected to be a massive spectacle with TV cameras lining the staid chamber. The room will be jampacked with lawmakers angling for their sliver of airtime.

The hearings are a chance for each lawmaker to show voters that they care about the public outrage surrounding the Cambridge Analytica scandal, even if Congress fails to pass any laws in response to the outcry.

Congress has grown increasingly worried about the role of social media sites in politics since it was revealed that Russia used platforms like Facebook and Twitter to interfere in the 2016 presidential election. Lawmakers have repeatedly questioned Facebook, Twitter and Google on issues like online security, online extremism and privacy, but Zuckerberg himself has not yet appeared for questioning. That has lots of lawmakers fuming.

Sen. Richard Blumenthal, D-Conn., a member of the both the judiciary and commerce committees, said in an interview with NPR's Morning Edition that he wants to know how many other firms could be violating Facebook policies and accessing sensitive user data.

"The company really is in a moment of reckoning," Blumenthal said. "The question is one of responsibility for individual data, and it goes well beyond Cambridge Analytica."

Zuckerberg got a first taste of the congressional hearing circus on Monday when he met privately with individual senators ahead of the hearing. While he faced questioning inside the offices, a sprawling crowd of reporters, tourists and onlookers gathered in the office building halls.

Viewers can expect a similar scene, complete with protesters, outside the hearing room as the cameras roll on Zuckerberg's testimony.

3. ... and they want to know about far more than just Cambridge Analytica

Lawmakers are also concerned about how Facebook regulates its massive online ad platform and what the company is doing to keep bad actors out of users' daily feeds.

Louisiana Republican Sen. John Kennedy, who is on the Judiciary Committee, said Sunday that the first question Zuckerberg should answer is: "Does he really know who is running ads on his platform?"

"Facebook's lawyers say they have 500,000 unique advertisers a month," Kennedy said in an interview on CBS' Face The Nation. "I don't think they know who is running ads and issue campaigns. We need to talk about how we're going to find out."

When it comes to digital advertising, Facebook and Google completely dominate the field, sometimes even being criticized as a duopoly on digital ad sales. This has prompted calls for an antitrust investigation of the industry.

Cable and telecom companies, for example, have historically pointed to the vast reach of Facebook and Google to present them as direct competitors, though competitors who don't face the same amount of regulatory oversight. In recent days, some broadband companies have been publicly calling for Congress to regulate privacy and the Silicon Valley giants.

4. Zuckerberg may not have the kind of answers they're looking for

Most lawmakers say they want clear and specific answers from Zuckerberg about what the company knew, when they knew it and what they're going to do to prevent privacy violations in the future.

But Zuckerberg may not be willing to go there.

In prepared remarks, Zuckerberg indicates he is grappling with the bigger identity of Facebook. For years, he has presented the social network as a neutral platform. Zuckerberg argues the company is not a media arbiter, but a tech firm firmly rooted in a law that shields Internet companies from legal responsibility for what people say and do online.

But now, Zuckerberg is expected to tell lawmakers that Facebook made a "big mistake" in taking such a narrow a view of its responsibility.

"It's not enough to just connect people, we have to make sure those connections are positive," he says in prepared testimony. "We have a responsibility to not just build tools, but to make sure those tools are used for good."

5. Some lawmakers say it's time to regulate how social media companies handle personal data. Facebook agrees — sort of

There isn't much Congress can do right now to change the way Facebook — or other social media companies — handle user data or who can buy ads on their platforms. Facebook is a private company and is not subject to existing rules about political advertising or user data — at least not in the United States.

Some lawmakers, like Florida Sen. Bill Nelson, the top Democrat on the commerce committee, told reporters on Monday that Congress has to think seriously about changing that, and Zuckerberg knows it.

"I believe that he understands that regulation could be right around the corner," Nelson said.

Internet companies' privacy practices are reviewed by the Federal Trade Commission, which investigates violations rather than sets pre-emptive regulations.

The FTC in 2011 had reached a settlement with Facebook after federal investigators alleged that Facebook did not warn people about changes to their privacy settings. The commission also alleged that Facebook allowed far more of users' data to be shared with advertisers and apps than it represented to users. The settlement did not include a fine, but it did set a number of new privacy requirements for Facebook.

Following the news of Cambridge Analytica's unauthorized data grab, the FTC — in a rare public acknowledgement — has confirmed it's once again investigating Facebook's privacy practices.

Outside of the U.S., regulations are on the way. The European Union has recently adopted landmark privacy standards that go into effect on May 25. Known as the General Data Protection Regulation, the rules require websites to get explicit consent from users before collecting any data. The new EU law also requires companies to disclose data breaches within 72 hours and to get parents' approval to carry personal data of children younger than 16. Violations would incur massive fines.

Zuckerberg has said that Facebook would roll out "the same controls and settings" in the United States as it does in Europe in May, although the rules may not have the same format. Privacy advocates in the United States have been urging lawmakers not only to press Zuckerberg on what exactly that means — but also to discuss writing privacy rules into U.S. laws as well.

But that may not be enough for some lawmakers like Sen. Ed Markey, D-Mass., who say Congress needs to act to ensure all companies follow the same rules.

Copyright 2018 NPR. To see more, visit http://www.npr.org/.