Facebook users are livid about the poor handling of Cambridge Analytica's data harvesting - and now #DeleteFacebook is trending

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Cambridge Analytica founder and whistleblower Christopher Wylie

• Over the weekend, Cambridge Analytica founder Christopher Wylie came forward to say that his company had gathered information from 50 million Facebook users and used it to target voters during the 2016 election, according to extensive reporting done by The Guardian. 
• Wylie said Facebook knew in 2015 that it had gathered information, and asked Cambridge Analytica to delete the data, but never followed up to check if it did. (Spoiler alert: It did not.) 
• Users angered by the irresponsible use of their data are taking to Twitter using the hashtag #DeleteFacebook and removing all Facebook-owned applications including Instagram and WhatsApp.

Over the weekend, news broke that a data firm known Cambridge Analytica used Facebook to harvest 50 million user profiles illegitimately, which was used to target voters during Trump's 2016 campaign for the US presidency, as well as the Brexit Leave campaign.

Cambridge Analytica, a data-analytics company that worked for the Trump campaign in 2016, pulled user information by paying people to take a quiz, and then proceeded to use the information it gathered from the users' friends without their permission, or permission from Facebook.

Cambridge Analytica founder Christopher Wylie came forward about the illegitimate use of data in an interview with The Guardian over the weekend, saying Facebook knew his company had gathered a large sum of data back in 2015. At the time, Facebook deleted the quiz and company lawyers sent a letter to Cambridge Analytica asking they delete the information, but Facebook never followed up to make sure the deed was done, according to Wylie.

Users are taking to Twitter to express their anger at the irresponsible use of their data, using the hashtag #DeleteFacebook:

The personal information that Cambridge Analytica pulled helped build psychographic profiles that assessed things like IQ, agreeableness, political views, and personality traits. The analysis was so in-depth that the company was able to categorize people into five "sensational interest" categories:

• "militarism" - guns and shooting, martial arts, crossbows, and knives
• "violent occultism" - drugs, black magic, paganism
• "intellectual activities" - singing and making music, foreign travel, the environment
• "credulousness" - the paranormal, flying saucers
• "wholesome interests" - camping, gardening, hill-walking

On March 16, more two years after the alleged data breach from Cambridge Analytica was first reported, and four days after the Guardian reached out to Facebook for comment, Facebook finally suspended Cambridge Analytica from its platform. A couple of days later, it suspended Wylie's Facebook and Instagram accounts.

Both companies are now under investigation, and Facebook's stock has dropped 8% from market close on Friday as of noon ET on Monday.