WASHINGTON • Facebook CEO Mark Zuckerberg has told US lawmakers that he was among the 87 million or so users of the social media network whose data was improperly shared with political consultancy Cambridge Analytica.
Wearing a dark suit and tie, and prefacing almost every remark with "congressman" or "congresswoman", Mr Zuckerberg on Wednesday repeatedly defended the company's privacy practices.
However, when asked if his data had been improperly used, he replied: "Yes."
Nevertheless, the chief executive of the world's largest social media network pushed back on Congress members' suggestions that users do not have enough control of their data on Facebook.
"Every time that someone chooses to share something on Facebook... there is a control. Right there. Not buried in the settings somewhere, but right there," the 33-year-old Internet billionaire told the US House of Representatives Energy and Commerce Committee.
Mr Zuckerberg's admission that his own data made its way into the hands of Cambridge Analytica laid bare that even the company's technologically adept founder was unable to protect his own information from parties seeking to exploit it.
But he stiffly defended Facebook's business model that uses the data and postings of the 2.2 billion users of its free platform in order to attract the advertising revenue the US$480 billion (S$629 billion) company depends on.
Mr Zuckerberg reiterated that the company had shut down the pipeline that allowed such data, including his own, to slip into the hands of third parties. However, he added that it will take many months to complete an audit of other apps to determine if they also improperly used data.
Mr Zuckerberg also said Facebook Inc collects information on consumers who are not registered as users, acknowledging something that has been reported but not publicly spelled out by the company.
"In general, we collect data on people who are not signed up for Facebook for security purposes," Mr Zuckerberg said.
Mr Zuckerberg said the practice was intended to help prevent malicious actors from collecting public information from Facebook users, such as names. "We need to know when somebody is trying to repeatedly access our services," he said.
His questioner, Representative Ben Lujan, a New Mexico Democrat, said the practice creates "shadow profiles".
"You have said everyone controls their data, but you are collecting data on people that are not even Facebook users, who have never signed a consent, a privacy agreement," Mr Lujan said.
The congressman said non-members of Facebook wanting to know what data the company holds are directed by the service to sign up for a page in order to see what information is being harboured.
"We have got to fix that," he said.
Facebook builds "shadow profiles" of people who are not users by accessing data from inboxes and smartphone contacts of those who are active users, Gizmodo and other publications have reported.
On Twitter, a former Facebook employee in the ad department, Mr Antonio Garcia Martinez, said Mr Zuckerberg's description of the data's use was incomplete.
"It is collected for growth reasons as well," he said, to make sure people have the right friend suggestions when they sign into the service for the first time.
REUTERS, AGENCE FRANCE-PRESSE, BLOOMBERG