Facebook's Mark Zuckerberg has promised to protect user privacy before. Will this time be different?

Jessica Guynn | USA TODAY

Show Caption Hide Caption Zuckerberg maintains 'Facebook is safe' The Facebook CEO expounds on his social platform's privacy controls and information that is shared with advertisers.

SAN FRANCISCO — Mark Zuckerberg has promised to protect people's privacy before. Will this time be any different?

That was the question looming as the Facebook CEO made an appearance on Capitol Hill on Tuesday and pledged to lock down the personal information of the social network's 2.2 billion users.

"I am committed to getting this right," Zuckerberg said during his testimony before a joint hearing of the Senate Committee on the Judiciary and the Senate Committee on Commerce, Science and Transportation.

Facebook users have become increasingly numb to privacy incursions in the age of big data. But revelations that the personal details of 87 million users, most of them in the United States, were improperly harvested by political consulting firm Cambridge Analytica and that Facebook's search tool allowed bad actors to scrape nearly all Facebook profiles have shaken public confidence and drawn hard scrutiny from lawmakers.

"I think most online-savvy Americans knew and understood that everything they put online was subject to review by analytics, but now everyone has gotten a big wake-up call," says Ava Roxanne Stritt, 54, a Facebook user and travel writer from Columbia, S.C.

Each time the social media giant has been called out for mishandling people's data, Zuckerberg smoothed things over by promising to give users more control over their personal information. Yet, for more than a decade, the 33-year-old billionaire tech executive has pushed Facebook users to bare more about themselves, cashing in on the thousands of pieces of data Facebook collects on each user to fuel its multibillion-dollar business.

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"I would expect that next year, people will share twice as much information as they share this year, and next year, they will be sharing twice as much as they did the year before," Zuckerberg predicted in 2008. Two years later, he argued that privacy was no longer a "social norm."

"Facebook wants us to forget that it has been explicitly and openly in favor of every one of us exposing ourselves maximally for years," says Siva Vaidhyanathan, professor of media studies at the University of Virginia and author of an upcoming book on Facebook, Antisocial Media.

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Facebook's past privacy blunders

• In 2006 after the introduction of News Feed, which suddenly began blasting users' personal lives to all of their friends in a daily feed, some 1 million users joined protest groups. Others protested outside Facebook's Silicon Valley headquarters. "We did a bad job of explaining what the new features were and an even worse job of giving you control over them," Zuckerberg said at the time.

• In 2007, Zuckerberg had to apologize for launching Beacon, which broadcast information about users' activities and purchases elsewhere on the Web without their permission.

• Also in 2007, Facebook invited third party developers to build apps to encourage users to spend more time on the giant social network, while giving outsiders access to vast amounts of valuable data on Facebook's users.

• New tools Facebook launched in 2009 that it said would give users more control over their information were criticized for pushing users to make even more of their information public, triggering an investigation by the Federal Trade Commission.

• In 2010, Facebook was caught sending information to advertisers that could be used to identify consumers without their consent. Facebook closed the privacy loophole and Zuckerberg conceded "sometimes we move too fast."

• Facebook reached a settlement with the FTC in late 2011. Regulators said Facebook claimed that third party apps only had access to the personal data they needed to operate. Instead apps could access nearly all of a user's data. Zuckerberg agreed to get user permission before collecting personal data and sharing it with others.

• In 2014, Facebook landed in hot water for playing with people's feelings. A psychological experiment conducted in 2012, the results of which were published in a scientific journal two years later, altered the news feeds of more than half million users to show them more positive or more negative status updates. Facebook's chief operating officer Sheryl Sandberg apologized, saying the experiment was "poorly communicated."

The current Facebook crisis began in summer 2014 when some 300,000 Facebook users downloaded a psychology app called This Is Your Digital Life. The researcher behind the app collected data not just on those users but on their Facebook friends and passed the data to Trump campaign-connected Cambridge Analytica. The U.K. firm uses data it collects to created detailed personality profiles of voters to sway them with targeted messages.

A 2015 article in the Guardian uncovered that tens of millions of Facebook users had their data harvested, many without their permission, but Facebook did not notify users. After the incursion came to light in a series of articles in The New York Times and The Observer last month, Facebook accused the researcher and Cambridge Analytica of violating company rules. Cambridge Analytica denies using the Facebook data on behalf of the Trump campaign during the 2016 presidential election.

The data leak struck a nerve. Critics say Facebook was repeatedly warned about abuses of its data rules by Cambridge Analytica and third-party apps and yet did too little about it.

Facebook now says it will spend millions investigating tens of thousands of apps that collected large amounts of user data, but the company admits it won't be able to track where all the data ended up or how it was used. On Tuesday, Facebook users began to receive notifications that their personal information was leaked to Cambridge Analytica.

Tori Tait, 35, a social media director from Murrieta, Calif., says she was alerted Tuesday that a Facebook friend downloaded the psychology app, putting some of Tait's personal information at risk. Tait says everyone needs to better understand what information apps collect when granted permission — including Facebook.

"Facebook themselves should have at minimum a moral obligation to better vet and monitor third-party apps," Tait said. "I think they need a level of responsibility that isn't typical of a social platform. There's just too much at stake otherwise."

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Never before has Facebook found itself in such hot water over data privacy.

This week, Zuckerberg is hoping to restore public trust by making two appearances before congressional committees, his first time testifying about a host of problems plaguing Facebook, from data-privacy leaks to foreign interference in the presidential election to false news. His testimony comes as Washington weighs regulation of the social media giant and an online Delete Facebook movement has attracted high-profile followers such as Elon Musk, Cher, Will Ferrell and Steve Wozniak.

"Consumers may not fully understand or appreciate the extent to which their data is collected, protected, transferred, used and misused," Senate Judiciary Committee Chairman Chuck Grassley, R-Iowa, said during the hearing.

In response, Zuckerberg's company has promised yet again to make it easier for users to adjust their privacy settings. And, years after being warned about the risks to consumers of letting users enter phone numbers or email addresses into its search tool to find other people, it has removed the feature.

Will people still be willing to trade their privacy for their Facebook friends?

Despite a track record of making hollow promises about the security of their data, many users say they are giving the Facebook CEO the benefit of the doubt.

"I realize that any and all info that I share with Facebook can be used for marketing purposes and any info I don't want shared I either set to private or just don't post at all," says Ane Urquiola Lowe, 34, a travel adviser and blogger from Austin.

Brandon Morrison, 30, a strongman coach and marketing coordinator from Grand Rapids, Mich., says he also wants to believe Zuckerberg will do the right thing by Facebook users.

"But I think that Facebook has grown to become a behemoth that even he doesn't fully understand the scope of anymore," Morrison said. "We will see what steps they take in the coming weeks, because it's absolute crunch time right now to restore faith in the online community."

Stritt says her faith in Facebook is wavering.

"I would say that I did not have much trust in the beginning," Stritt said of Facebook, "but now that has dwindled down to almost none."