Facebook CEO Mark Zuckerberg was grilled before the Senate Commerce and Judiciary Committees in a Tuesday hearing that lasted hours.

Zuckerberg reiterated numerous times in both written and spoken testimony that, yes, the company made mistakes when dealing with Cambridge Analytica, the now-maligned British data analytics firm that worked with the Donald Trump presidential campaign. He also underscored the numerous new policies that Facebook has been rolling out in recent days, ranging from ad monitoring to more Burmese language support, among other changes.

Many senators used the opportunity to impress upon the executive that it may no longer be a completely fair trade for the company to happily absorb vast quantities of free information voluntarily shared on Facebook and for Facebook to make vast sums of money as a result.

One of the first senators to make this argument was Sen. Bill Nelson, a Florida Democrat, who wondered if the company would consider allowing more privacy-minded users to pay for the service rather than simply provide related advertising based on what users share with the company. Previously, Facebook representatives have not responded to Ars' asking of this same question.

"Are you actually considering having Facebook users pay for you not to use that information?" Sen. Nelson said.

"In order to not run ads at all, we would still need some sort of business model," Zuckerberg answered. "We think offering an ad-supported service is most aligned with our mission of connecting everyone in the world."

Later on, however, Zuckerberg seemed to leave the door open to an ad-free, paid service, when he told Sen. Orrin Hatch (R-Utah): "There will always be a version of Facebook that will be free."

Moments later, Hatch asked: "How do you sustain a business in which users don't pay for your service?"

"Senator, we run ads," Zuckerberg said. (Facebook raked in $40 billion in ad revenue in 2017 alone.)

Later on, while being questioned by John Cornyn (R-Tex.), Zuckerberg pointed out that Facebook does not sell data to advertisers.

"But you clearly rent it," Cornyn retorted quickly.

The 33-year-old CEO also mentioned numerous times that Facebook users own their own data.

But one senator wasn't buying it.

"It doesn't seem to me that we own our own data, otherwise we'd be getting a cut," Sen. Brian Schatz, a Hawaii Democrat, told him.

Kill them with kindness

Overall, the CEO was cool under pressure and tried to be straightforward and even helpful with senators that clearly sometimes did not fully understand what they were asking.

Zuckerberg even conceded to Senator Amy Klobuchar (D-Minn.) that he would be open to a rule that would require Facebook to notify its users of a breach or any other seeming unauthorized data usage within 72 hours.

He also revealed, for the first time, that Facebook has responded to subpoenas from the offices of Special Counsel Robert Mueller.

Sen. Richard Blumenthal (D-Conn.) slammed Zuckerberg, asking if Facebook’s behavior now regarding Cambridge Analytica violated its 2011 consent decree with the Federal Trade Commission. Zuckerberg said that his company had not.

Blumenthal continued: