"This is Your Digital Life", was a personality quiz app that collected data not only on people who took it, but also collected data from their friends, including details that may not have meant to share publicly.
He was appearing in front of a joint session of several United States senate committees, after it was revealed in recent weeks that about 87 million people had their profile information accessed by marketing firm Cambridge Analytica. Says Zuckerberg, that "goes for fake news, foreign interference in elections, and hate speech, as well as developers and data privacy". Several countries like India, Pakistan will have elections.
But despite Mr Zuckerberg's apologies for the scandals and his description of combating Russian hackers as an "arms race", it does not appear to have affected the company's worth.
Asked if Facebook executives have been interviewed by Special Counsel Robert Mueller, who is investigating Russian interference in the U.S. election, Zuckerberg said: "Our work with the special counsel is confidential".
"We face a number of important issues around privacy, safety, and democracy, and you will rightfully have some hard questions for me to answer", Zuckerberg said.
Speaking during his testimony in front of the US Congress, he was asked if Facebook would always remain a "free" product to which he responded by saying, "There will always be a version of Facebook that is free".
So, CA may have obtained Zuckerberg's data through the privacy loophole that his own company left open.