“Congresswoman, yes…”

“Senator, no…”

“Congressman, we already do that.”

Facebook CEO Mark Zuckerberg patiently explained his platform to occasionally befuddled U.S. lawmakers without making any promises to overhaul it in the face of regulation, in a marathon two-day Congressional hearing to address the social media giant’s use and potential misuse of personal data.

Zuckerberg repeatedly apologized for the Cambridge Analytica data breach and acknowledged that regulation of his platform appears to be “inevitable,” but never went so far as to promise any specific changes to the social media behemoth that – he frequently pointed out – began in his Harvard dorm room.

Here’s what we learned from Zuckerberg’s 10 hours of testimony before the Senate on Tuesday and the House on Wednesday.

What is Facebook, and how should it be regulated?

This was one of the central questions of the hearing, although it still created a lot of confusion.

Many lawmakers tried to hammer out a definition of Facebook as a company, in hopes of finding an existing industry model to regulate it. Is it an essential communication service, like the telephone? Is it a monopoly that’s become too powerful and needs to be broken up? Or is it a media company, and therefore responsible for the content published on its platform?

Zuckerberg rejected those suggestions, saying he considers it a “technology company” that employs programmers to write code. He added that the company has interests in many fields – including running aircraft – but he doesn’t think that makes it an aerospace company.

However, he also acknowledged that it’s probably a matter of time until regulation becomes necessary.

“The internet is growing in importance around the world in people’s lives, and I think that it is inevitable that there will need to be some regulation,” he said.

But like, what IS Facebook?

While some were trying to engage with the finer points of Facebook’s business model, many elder statesmen – particularly in the Senate, where the average age is 62 – appeared to have an extremely tenuous grasp of social media in general, leading critics to compare Zuckerberg’s testimony to a tech support session.

Republican Sen. Orrin Hatch, 84, asked Zuckerberg how Facebook makes money.

“Senator, we run ads,” Zuckerberg said, smirking.

“How can someone control keeping the content within the realm they want it to without being collected?” asked Markwayne Mullin, R-Okla.

“If you don’t want any data to be collected around advertising, you can turn that off and we won’t do it,” Zuckerberg said. In other words, users can turn off targeted ads on the platform, or restrict what information they provide.

Many basic questions were repeated by multiple lawmakers over the two days of testimony.

Some asked how Facebook gets data in the first place. It’s voluntary, Zuckerberg pointed out.

Others suggested Facebook ask people before it allows third parties to look at their data. It does, Zuckerberg said.

One asked if he could take his personal data and go to another social media platform with it – as if it were the same as withdrawing your money from one bank and taking it to another. Zuckerberg said there’s nothing stopping anyone from giving their personal info to another social media platform. He also pointed out that users can download Facebook’s file on them to see what the company has access to.

A handful of individuals even went so far as to hold up their phones or tablets to demonstrate that they know how to use Facebook.

“It’s wonderful for us seniors to connect with our relatives,” said Congressman Gus Bilirakis, R-Fla.

Zuckerberg cares about his privacy

According to the New York Times, Zuckerberg spent quite a bit of time, money and effort to prepare for the hearing, hiring coaches to grill him on questions he might face during his marathon sessions before the Senate and Congress. He answered most of his questions carefully, starting each response with the word “Congressman,” “Congresswoman” or “Senator.”

But Illinois Sen. Dick Durbin managed to hit the billionaire with a curve ball that caught him off guard.

“Mr. Zuckerberg, would you be comfortable sharing with us the name of the hotel you stayed in last night?” Durbin asked on Tuesday.

“Um,” Zuckerberg said. He paused, smiled awkwardly, shook his head and licked his lips. “No,” he finally said, drawing laughter from the room.

Durbin continued to press him on the issue. “If you messaged anybody this week, would you share with us the names of the people you messaged?”

“Senator, no, I would probably not choose to do that publicly here,” Zuckerberg replied.

“I think maybe this is what this is all about: Your right to privacy,” Durbin said. “The limits of your right to privacy and how much you give away in modern America in the name of ‘connecting people around the world.’”

Zuckerberg responded by saying: “I think everyone should have control over how their information is used.”

He also said his own personal data was exposed in the Cambridge Analytica breach.

Yes, Facebook can figure out what you’re doing even when you’re logged out

Zuckerberg acknowledged that Facebook continues to keep track of users’ behaviour even when they’re logged out of its service.

“There have been reports that Facebook can track a user’s internet browsing activity even after that user has logged off of the Facebook platform,” Sen. Roger Wicker said on Tuesday. “Can you confirm whether or not this is true?”

“Senator, I want to make sure I get this accurate so it would probably be better to have my team follow up afterwards,” Zuckerberg said.

“You don’t know?” Wicker pressed.

“I know that people use cookies on the internet, and that you can probably co-relate activity between sessions,” he said. “We do that for a number of reasons, including security and including measuring ads to make sure that the ad experiences are the most effective, which of course people cannot doubt of (sic), but I want to make sure that I’m precise in my answer so let me follow up.”

Facebook needs your data to make money

One of the tensest moments of the hearing came on Wednesday, when Frank Pallone, R-N.J., asked Zuckerberg for a yes-or-no answer on data collection – and did not receive the answer he asked for.

Pallone asked Zuckerberg to commit to minimizing the amount of personal data collected from users under Facebook’s default settings, “to the greatest extent possible.

“I don’t think that’s hard for you to say yes to, unless I’m missing something.”

“Congressman, this is a complex issue that I think deserves more than a one-word answer,” Zuckerberg replied.

Facebook’s business model is reliant on collecting users’ data, as Zuckerberg pointed out in another moment at Tuesday’s Senate hearing.

“We do not sell data to advertisers,” Zuckerberg said. “What we allow is for advertisers to tell us who they want to reach. And then we do the placement.”

In other words, Facebook uses data provided by users to help advertisers target them based on location, interests, age and shopping habits. Users can opt out of this, but the whole system is essentially a honey trap: the more info a given Facebook user shares with friends, the more likely they are to receive ads targeting their specific behaviours.

But Facebook isn’t turning this personal data over wholesale to advertisers or third parties. Instead, third parties are simply asking for – and often receiving – people’s data through Facebook enabled apps. Anyone who plays a game on Facebook, for instance, will be prompted with a page asking for access to certain profile information before proceeding. This can including basic info such as a user’s profile picture and email address, or more invasive data such as relationship status or a list of friends.

Cambridge Analytica is accused of using a quiz app to ask for data in this manner, before turning around and using the data it harvested for other purposes. The company has denied the allegations that it misused data to influence the 2016 U.S. presidential election.

The internet is a savage and hilarious place

No one is safe from ridicule on the internet – not even the founder of its most successful social media platform.

Online users eviscerated Zuckerberg with a deluge of memes inspired by his testimony, mocking everything from his seemingly robotic appearance to the very deliberate manner in which he sipped his water.

Some also pointed out that the 33-year-old tech billionaire, who is five-foot-seven, was using a booster seat.

With files from The Associated Press