European and US authorities are demanding answers from Facebook Inc after personal information on 50m users of the social media site were leaked to UK company Cambridge Analytica, which helped the Vote Leave and Trump presidential campaigns in 2016.
US senators are calling for Facebook's CEO Mark Zuckerberg to explain how the personal information of millions of its users ended was without their permission or knowledge, while a parliamentary committee investigating fake news has accused both companies of misleading MPs.
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Joseph Chancellor, a social psychology researcher at Facebook, allegedly provided Global Science Research (GSR) with Facebook users' personal information through permissions they gave to carry out a personality quiz app. GSR's Aleksandr Kogan, a Cambridge academic, provided such information to Cambridge Analytica without permission from Facebook. In 2015 when the social media platform found out, they asked for assurance that the data had been deleted.
According to the New York Times, not only was the data not deleted but there are suspicions that it may have been used in advertising Trump's electoral campaign in 2016, with authorities also concerned that Facebook may have violated the privacy of its users in many occasions.
Cambridge Analytica uses information gathered to develop a more sophisticated psychological profile of internet users, including "shaping" the Trump campaign around information it has gleaned on more than 200m American citizens.
Facebook had denied that harvesting of user profiles by Cambridge Analytica was a data breach but confirmed that Kogan had "lied to us and violated our 'platform policies' by passing data from an app that was using Facebook Login to SCL/Cambridge Analytica".
The Seattle-based company said it is investigating its hiring of Chancellor, who is identified in corporate documents as an official of the parent company of Cambridge Analytica, SCL, which combines data mining and analysis to 'serve' tailored communications to voters during elections and has repeatedly denied wrongdoing or improper use of Facebook data.
"We worked with Facebook over this period to ensure that they were satisfied that we had not knowingly breached any of Facebook's terms of service and also provided a signed statement to confirm that all Facebook data and their derivatives had been deleted," Cambridge Analytica said in a statement over the weekend.
Christopher Wylie, a former employee of Cambridge Analytica, told the Observer that there were multiple copies of the profile data.
The UK firm was also put under the microscope at home last year after suggestions that it had influenced the Brexit referendum vote.
Writing in an article in February 2017, CEO Alexander Nix boasted he had "helped supercharge Leave. EU's social media campaign by ensuring the right messages are getting to the right voters online."
When questioned last month by parliament's fake news enquiry, Nix said: "We do not work with Facebook data and we do not have Facebook data."
The use of Facebook for political purposes has been scrutinised by the UK electoral regulator, which last year carried out an investigation to establish whether one of the main pro-Brexit campaign groups broke election spending rules. Vote Leave paid £675,000 to fashion student Grimes to cover his bill from AggregateIQ, a data analysis agency that produce a targeted Facebook marketing campaign ahead of last June's vote. Veterans for Britain, a separate group, received £100,000 from Vote Leave.
Facebook has previously trumpeted of the power of its political advertising wing, claiming its "integral" contribution to Polish election in 2015, won by Andrzej Duda, and in the 2015 UK general election, boasting how the SNP dominated results in Scotland through a "powerful combination of Facebook's targeting and engagement tools".