Cruz then asked Zuckerberg if he was aware of any Facebook page being taken down from Planned Parenthood, which is richly rewarded by the Democrats. And doubtless uses that data to serve up the right audiences to advertisers-which is the company's main revenue model. Facing tough questioning in the second day of high-stakes hearings in Congress, the 33-year-old CEO conceded that regulation of social media companies - under mounting scrutiny over the misuse of user data - is "inevitable". How much information does Facebook collect about its users? The other, of course, was ad targeting.
He answered questions for 5 hours from the House Committee on Energy and Commerce one day after his joint hearing with the Senate judiciary and commerce committees.
Zuckerberg had no quarrel with the argument. But what's in the new rules? "A lot of that depends on you".
It's actually as easy as a click of your mouse (or a tap of your finger!). I took to the rainy streets of Seattle's Fremont neighborhood to find out.
On Tuesday Zuckerberg disclosed his company is working with special counsel Robert Mueller's investigation of Russia election meddling after a pro-Trump data mining firm accessed at least 87-million users information without their knowledge.
With news about Facebook and its data sharing and selling practices in hyperfocus this week, it's important to know if the platform is using your data.
Businesses can upload their data to Facebook to see if the ads they run on Facebook lead to sales in their stores; they do this via something Facebook calls offline conversions.
Long pointed out that the timing seems awfully coincidental, but Zuckerberg remained steadfast that the two were unrelated.
"To a great many Americans, that appears to be a pervasive pattern of political bias", Cruz said. Some 300,000 users downloaded the app and in turn tens of millions of their friends' data was also accessible.
Facebook makes its money by leveraging user data in order to serve users ads it thinks are pertinent.
The proposed law, dubbed the CONSENT Act, would also federally require web and tech companies - like Facebook - to notify users in the event of a breach, instead of reporting through state attorney generals.
"I don't think that we're comedians", Hardaway told Laura Ingraham. But when asked if his data had been improperly used he replied: "Yes".
Still, Lujan pointed to the challenge faced by people who don't use Facebook but want to see what the social network knows about them.
These facial clues can help viewers figure out whether a speaker - Zuckerberg in this case - is saying what he means.
The US Federal Trade Commission is investigating whether Facebook violated an agreement it signed with the agency in 2011 by its actions in the Cambridge Analytica scandal.