In early 2018, Facebook admitted to mishandling data from over 50 million Facebook users which had been improperly obtained by political data-analytics firm Cambridge Analytica.
Here's the full story thus far:
What did Cambridge Analytica do?
Cambridge Analytica harvested information from over 87 million Facebook users through an external app in 2015.
The data came from a personality quiz, which around 270,000 people were paid to take. The quiz "thisisyourdigitallife" in turn pulled data from their friends' profiles as well, ending in the enormous data stash.
In March 2018, a Cambridge Analytica employee named Christopher Wylie (above) was responsible for revealing the extent of the data firm's activities in interviews with The Guardian and The New York Times.
What data did they get?
Cambridge Analytica harvested personal information on where users lived and what pages they liked, which helped build psychological profiles that analyzed characteristics and personality traits.
This kind of information was later deployed in political campaigns.
Wylie said: "We exploited Facebook to harvest millions of people's profiles. And built models to exploit what we knew about them and target their inner demons."
Where did it come from?
The quiz was created by Aleksandr Kogan, a Russian psychology professor at the University of Cambridge, who shared the information in a commercial partnership with Strategic Communication Laboratories (SCL), which later created Cambridge Analytica.
Trump's campaign hired Cambridge Analytica in June 2016 to help target ads using voter data gathered from millions of adults in the US.
Cambridge Analytica also assisted Brexit Leave campaigners in the run-up to the EU referendum.
Was it legal?
Facebook has contested whether the information was really taken without consent.
It said in 2018 : "People knowingly provided their information, no systems were infiltrated, and no passwords or sensitive pieces of information were stolen or hacked."
Also, Kogan could have broken Facebook's own rules by using the data for commercial rather than strictly academic purposes.
How is Facebook implicated?
Facebook said it removed the Cambridge Analytica quiz app from the platform in 2015 and demanded that Kogan, Wylie, and Cambridge Analytica confirm that they had deleted all the data harvested.
Wylie, however, claimed that Facebook only demanded that he remove all the Facebook data in August 2016, and they were small steps.
He said: "They [Facebook] waited two years and did absolutely nothing to check that the data was deleted. All they asked me to do was tick a box on a form and post it back."
When the story first broke in early 2018, raw copies of the data obtained by Cambridge Analytica were still available online, The New York Times reported .
Does this change Facebook and Cambridge Analyticas previous testimonies?
Alexander Nix, CEO of Cambridge Analytica, denied working with Kogan as well as using Facebook data. "We do not work with Facebook data and we do not have Facebook data," Nix told British MPs, as cited by The Guardian.
Facebook has also denied that it gave Cambridge Analytica data.
Simon Milner, the company's UK director of policy, told British MPs in 2018: "They [Cambridge Analytica] may have lots of data, but it will not be Facebook user data. It may be data about people who are on Facebook that they have gathered themselves, but it is not data that we have provided."
Facebook has since suspended Cambridge Analytica, its parent company Strategic Communication Laboratories, and Wylie from its platform. Wylie was also suspended from WhatsApp and Instagram, which are both owned by Facebook, The Observer's Carole Cadwalladr reported .
Is Russia involved?
Possibly. Wylie's testimony has revealed a Russian connection to Cambridge Analytica and Kogan.
The company was interested in understanding the link between data, behavioral microtargeting, and political campaigns, and met Cambridge Analytica at least three times between 2014 and 2015, The New York Times reported .
Wylie told The Guardian: "It didn't make any sense to me ... Why would a Russian oil company want to target information on American voters?"
Kogan, the Cambridge academic, had also been an associate professor at St. Petersburg State University and received Russian government grants while creating and harvesting Facebook data through the app, The Guardian reported .
Curiously, Kogan's work in Russia was never publicized, and colleagues told The Guardian "no one knew" about it. Cambridge University said it was carried out in a "private capacity."
Then in 2019, Facebook got slapped with a massive $5 billion fine by the Federal Trade Commission.
Facebook was hit with a $5 billion fine from the Federal Trade Commission as part of a settlement over claims the company mishandled user data
The fine is a record for the FTC perhaps a precedent for the kind of punishment that tech giants could expect for mishandling users' data and is a direct response to the Cambridge Analytica scandal.
And now, the latest news about the ongoing controversy is that Facebook was aware of Cambridge Analytica far earlier than it previously said.
On Friday, NBC's Dylan Byers published a copy of an internal Facebook message thread from September 2015 where employees talked about "clients in the political space."
One such client, Cambridge Analytica, is described in the correspondence as, "a sketchy (to say the least) data modeling company."
In the emails, employees go into far more detail and even discuss a potential investigation into data scraping by political partners.
It wasn't until December 2015 when Facebook first realized the extent of Cambridge Analytica's data scraping practices and began to act on it.
In short, Facebook employees were flagging potential concerns related to Cambridge Analytica's practices as early as September 2015, but the company didn't act until March 2018.