Here’s everything you need to know about the Facebook scandal (and why it matters)

Facebook has faced worldwide controversy this week centred on a data company whose CEO boasted he had helped Donald Trump win the 2016 election.

The company, Cambridge Analytica, allegedly used data from 50 million Facebook profiles, according to a whistleblower from within the company.

The news, exposed by the Guardian, Channel 4 and others, has sent shockwaves around the world.

At one point, the scandal had wiped $50 billion (£35 billion) off the value of Facebook – and has prompted a #deletefacebook campaign to trend worldwide as users worry about how their data is being used.

Here’s what you need to know about Cambridge Analytica, Donald Trump and Facebook.

What is Cambridge Analytica accused of doing wrong?

The scandal centres on data from 50 million Facebook users harvested in 2013, which a whistleblower within Cambridge Analytica, Christopher Wylie, alleges was used to target adverts to American voters in 2016.

Executives from the firm were also covertly filmed, claiming they had ‘won the election’ for Trump, and boasting of using bribes and blackmail in elections around the world.

Cambridge Analytica allegedly used the data to target personalised adverts (ie ones that no one else could see) to voters to persuade them to vote Trump.

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The problem is where the data came from: it was ‘harvested’ from a personality quiz by Cambridge researcher Aleksandr Kogan, and passed to Cambridge Analytica.

Facebook says he violated the terms of service by handing the data to Cambridge Analytica.

Cambridge Analytica denies the claims.

What is Facebook accused of doing wrong?

Facebook claims that it is the victim in the case, saying that executives were ‘deceived’ in how the data was going to be used.

But the scandal has thrown light on how much data Facebook collects on users, and how it can be used in the political arena.

Politicians in America, Europe and Britain have called for an investigation – and some have suggested increased regulation on how social networks use people’s data.

Theresa May’s spokesman said, ‘It’s essential people can have confidence that their personal data can be protected and used in an appropriate way.

‘It is absolutely right the information commissioner is investigating this matter and we expect Facebook, Cambridge Analytica and all the organisations involved to cooperate fully.’

How did one quiz harvest data from 50 million people?

The app harvested information from not only the 237,000 people who did the quiz, but also their friends – leading to up to data from up to 50 million people being harvested.

At the time, this was allowed under Facebook’s terms of service (TOS), and the app was one of hundreds, if not thousands, which harvested data in this way.

Facebook changed the rules to prevent apps harvesting data from ‘friends’ in 2014: now apps are only allowed to ‘read’ the profiles of people who actually use them.

Why is Facebook data so useful in politics?

Facebook data includes a huge amount of information on people – such as where they live, their age, their friends, their spending and products they like.

It also includes words people have used in private messages, for instance.

This information can be used to target ‘personalised’ adverts to voters: adverts which only they will see, customised to appeal to them.

Facebook data can be combined with data from voter rolls and ‘data brokers’ to build profiles of actual voters – including their ‘Likes’ and dislikes.

Cambridge Analytica whistleblower Christopher Wylie said that he dealt with Trump team members such as Steve Bannon as early as 2014.

Wylie claims the company built software to predict people’s choices at the ballot box and influence the way they would vote.

How was it allegedly used in the Trump campaign?

The 50 million profiles allegedly obtained by Cambridge Analytica represented nearly a quarter of potential American voters.

The data was allegedly used along with other data purchased from other sources, for ‘psychographic’ targeting of advertising.

In covert recordings shown by Channel 4, executives from Cambridge Analytica said the data was used to target ‘unattributable and untrackable’ video adverts.

An executive said, ‘We just put information into the bloodstream of the internet and then watch it grow, give it a little push every now and again over time to watch it take shape.

‘And so this stuff infiltrates the online community, but with no branding, so it’s unattributable, untrackable.’

Cambridge Analytica executives were filmed claiming that the adverts were used in a targeted way to ensure Trump won.

Chief Data Officer Alex Tayler said, ‘When you think about the fact that Donald Trump lost the popular vote by 3 million votes but won the electoral college vote, that’s down to the data and the research.’

What has Cambridge Analytica said?

Cambridge Analytica has denied any wrongdoing, saying that it deleted the Facebook data when it realised it violated data protection laws.

The firm describes Christopher Wylie’s allegations as ‘false’ and claims he was a contractor, not a founder of the company.

The firm suspended CEO Alexander Nix in the wake of covertly filmed video which showed him claiming to have swung the election for Donald Trump.

The firm says, ‘The Board of Cambridge Analytica has announced today that it has suspended CEO Alexander Nix with immediate effect, pending a full, independent investigation.

‘In the view of the Board, Mr. Nix’s recent comments secretly recorded by Channel 4 and other allegations do not represent the values or operations of the firm and his suspension reflects the seriousness with which we view this violation.’

What has Facebook said?

Facebook has said in a statement, ‘The entire company is outraged we were deceived. We are committed to vigorously enforcing our policies.’

What has Mark Zuckerberg said?

Zuckerberg – belatedly – spoke publicly about the incident on Wednesday night, admitting mistakes and outlining steps to protect user data.

He broke more than four days of silence as he posted an update saying his company has a “responsibility” to protect its users’ data, and “if we can’t then we don’t deserve to serve you”.

His prolonged silence had led to users asking, ‘Where’s Mark?’

The company had previously said in a statement, ‘Mark, Sheryl and their teams are working around the clock to get all the facts and take the appropriate action moving forward, because they understand the seriousness of this issue.’

What can I do to protect my data?

A campaign to ‘Delete Facebook’ has swept the internet since the Cambridge Analytica revelations.

A Yahoo guide to how to deactivate or delete your account can be found here.

The Cambridge Analytica scandal revolves around private data harvested by an app – and you can also control how apps use your data on Facebook.

Go to the go to the top-right menu icon (in the desktop version of Facebook), then click Settings, then click ‘Apps’.

You’ll see a list of apps which you’ve authorised (for instance, Facebook quizzes, or phone apps you’ve logged into with Facebook details).