Stunning news about Facebook and an overseas data research firm, Cambridge Analytica, creates a major problem for the social media giant. The firm in Cambridge, England, harvested information from about 50 million Facebook users without their consent as part of its work for Donald Trump’s presidential campaign in 2016. The data was gathered through a phony survey by a British psychology professor, a violation of Facebook rules. He and the unethical firm are kicked off the site, as is a former Cambridge Analytica executive who told The New York Times and The Guardian (a London newspaper) about the mischief.

The personal information was used to identify voters considered receptive to Trump's messages so that his campaign – which isn't accused of wrongdoing – could aim ads, rally invitations and donation requests at them. The resulting uproar raises fresh concerns about how Facebook data can be used without consent and causes the company's stock market value to plunge. The U.S. Federal Trade Commission opened an investigation and the Republican-controlled Senate Commerce Committee wants answers from Facebook. The British government also will conduct a formal inquiry. At an individual level, some Facebook users – maybe many – are closing their accounts. Tweets with the hashtag #DeleteFacebook went viral last week. "The resulting backlash is Facebook's worst crisis since it was founded by Mark Zuckerberg and others in 2004," says The New York Times.

Zuckerberg, the 33-year-old chief executive, acknowledges: "We made mistakes, there's more to do and we need to step up and do it." He vows to limit access by app developers, such as those used for quizzes and games, to protect users' profiles and other data. "This was a breach of trust between [Professor Aleksandr] Kogan, Cambridge Analytica and Facebook," Zuckerberg posted last week. "But it was also a breach of trust between Facebook and the people who share their data with us and expect us to protect it." The company pledged to do better in full-page newspaper ads Sunday.

His company's post-election fumbling was already a major story before the latest embarrassment. It initially brushed off suggestions that Russian-based meddlers used the platform extensively in 2016 to spread misinformation and mounted other election interference efforts – activities it now acknowledges occurred. "With each new revelation about manipulation on its platform, it becomes increasingly clear that Facebook has, at least to some extent, lost control of its technology," writes Columbia Journalism Review. "It's also apparent that users, by and large, aren't aware the privacies they're forfeiting."

Facebook founder says: "We have a responsibility to protect your data, and if we can't then we don't deserve to serve you, " – Mark Zuckerberg, March 21 post

Editorial says: "Facebook says it takes this case seriously. But it is clear that lawmakers cannot rely on the company to police itself." – The New York Times

Senator says: "This is a major breach that must be investigated. It's clear these platforms can't police themselves. I've called for more transparency and accountability for online political ads. They say 'trust us.' Mark Zuckerberg needs to testify before Senate Judiciary [Committee]." – Tweet by Sen. Amy Klobuchar, D-Minn.