But for many, the benefits of Facebook's social connectedness and sense of intimacy outweigh the costs, said journalism professor George Sylvie, an expert on technology's role in media. "We're gratified [with the development]", said Alastair Mactaggart, a proponent of an initiative called Californians for Consumer Privacy.
A key discussion in the five-hour hearing was the urban legend that Facebook secretly records audio through microphones on a phone to target advertisements to users.
"Right there. Not buried in the settings somewhere but right there", Zuckerberg said. It wasn't clear to me who they are and under what circumstances they got that information. He had two encounters, one with the Senate and one with the House.
Confirming that a telephone conversation took place earlier today, Jourova said that she "urged Facebook to fully cooperate with the European investigators, also on the highest level from the company".
Facebook also makes use of social media plug-ins and cookies - tracking devices that follow a user's internet activity - to collect data via third-party websites.
Zuckerberg has been providing testimony this week to three congressional committees, addressing the manner in which Facebook's user data was improperly accessed by Cambridge Analytica. He gave no further details.
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What Mark Zuckerberg really earns
If the people that represent us really want to hold Zuckerberg and Facebook accountable, we should be able to call his bluff. On a question, if Facebook has a political bias, he said the platform's goal was not to engage in political speech.
Back in 2011 and 2012, while the Lewiston native was working as an operations manager for Facebook, he warned his supervisors that the company was not doing enough to protect the data of its users.
Facebook has been under scanner from the time news broke last month that the personal information of 87 million users had been illegally harvested by political consultancy firm Cambridge Analytica in an attempt to influence political outcomes.
It felt as though the company made a calculated decision to deflect rather than talk openly about the scope of Facebook data collection and its data-based ad system.
Business development director Vesselin Popov insisted it was opt-in only and was in line with Facebook's policies at the time, so was not at all like the app developed for Cambridge Analytica by Dr Kogan. "I do think that we can do a better job of explaining how advertising works", Zuckerberg said as he finished his response, but he did not explain that Facebook's ad system works by harnessing all the pieces of information from social network users.
In total, Facebook's stock has gained 4.5 percent since the start of the hearings, CNN Money reports. "But I am committed to getting this right, and that includes the basic responsibility of protecting people's information, which we failed to do with Cambridge Analytica", he said.
The Facebook finder and CEO owns more than 401.4 million shares in his company, and following the rise in stock prices, his stake is now worth $66bn (£46.2bn).