An academic who created an app which harvested data from 50 million users says he has been made "a scapegoat" for Facebook and Cambridge Analytica.
Dr Aleksandr Kogan completed work for Cambridge Analytica in 2014, but said he had no idea the data would be used for Donald Trump's election campaign.
The psychology academic told the BBC he wanted the data so he could model human behaviour through social media.
Facebook says Dr Kogan violated the site's policies.
The Cambridge University researcher developed a personality survey called This is Your Digital Life.
About 270,000 users' data was collected, but the app also collected some public data from users' friends.
Cambridge Analytica whistleblower Christopher Wylie said that, as a result, the data of about 50 million users was harvested for the analysis firm.
Both Cambridge Analytica and Facebook deny any wrongdoing.
Dr Kogan told BBC Radio 4's Today programme that he was "stunned" by the allegations made against him as he was advised the app was entirely legal.
He said: "The events of the past week have been a total shell shock, and my view is that I'm being basically used as a scapegoat by both Facebook and Cambridge Analytica when... we thought we were doing something that was really normal.
"We were assured by Cambridge Analytica that everything was perfectly legal and within the terms of service."
He said he was following advice given to him by Cambridge Analytica, and added he had "no reason to doubt" that was breaking any policy with Facebook.
He added: "One of the great mistakes I did here was I just didn't ask enough questions."
He also said the accuracy of the dataset had been "exaggerated" by Cambridge Analytica, and said the dataset was more likely to hurt Mr Trump's campaign.
What is the row about?
In 2014 a Facebook quiz invited users to find out their personality type.
As was common with apps and games at that time, it was designed to harvest not only the user data of the person taking part in the quiz, but also the data of their friends.
Facebook has since changed the amount of data developers can gather in this way.
Mr Wylie alleges that the data of some 50 million users, mainly in the US, was harvested without their explicit consent via their friend networks.
He claims the data was sold to Cambridge Analytica - no connections with Cambridge University - which then used it to psychologically profile people and deliver pro-Trump material to them.
The firm's chief executive Alexander Nix - who was suspended on Tuesday - was secretly recorded in a Channel 4 investigation saying the London-based company ran Donald Trump's digital campaign during the 2016 US election.
He said that the company's work, including research, analytics and targeted campaigning, allowed the Republican candidate to win with a narrow margin of "40,000 votes" in three states.
"We did all the research, all the data, all the analytics, all the targeting, we ran all the digital campaign, the television campaign and our data informed all the strategy," he added.
Before Channel 4 News had broadcast any of the secret filming, Mr Nix told the BBC's Newsnight programme he felt the firm had been "deliberately trapped".
What investigations are under way?
On Tuesday a parliamentary committee called for Facebook boss Mark Zuckerberg to give evidence about the use of personal data by Cambridge Analytica.
Damian Collins, the chairman of the Commons inquiry into fake news, accused Facebook of previously "misleading" the committee, and said it was "now time to hear from a senior Facebook executive with the sufficient authority to give an accurate account of this catastrophic failure of process".
US senators have called on Mr Zuckerberg to testify before Congress about how Facebook will protect users.
The head of the European Parliament said it would investigate to see if the data was misused.
The consumer watchdog the US Federal Trade Commission - which has the power to levy large fines - has also reportedly opened an investigation into Facebook.
On Tuesday a Cambridge University spokesperson said they had "sought and received assurances" from Dr Kogan that no University data, resources or facilities were used for his work and they had found no evidence to contradict that, but were writing to Facebook to "request all relevant evidence in their possession".
The UK's Information Commissioner Elizabeth Denham said she would be applying to court for a warrant to search the offices of Cambridge Analytica.
There have also been calls for an investigation into the work Cambridge Analytica carried out during the 2013 election in Kenya.
How have Facebook and Cambridge Analytica responded?
Both firms deny doing anything wrong.
Facebook has said the data was obtained legitimately, but Cambridge Analytica failed to delete it when told to do so.
A Facebook spokesperson said Dr Kogan was not allowed to transfer data to Cambridge Analytica, a third-party who would use the set for commercial purposes.
They added that sharing users' friends data outside the app was also against Facebook's rules.
The firm will send representatives to Washington on Wednesday to answer questions before the US Congress.
For its part, Cambridge Analytica says it deleted the data when told to by Facebook.
The firm suspended its boss Alexander Nix on Tuesday following his comments which appeared to suggest tactics his company could use to discredit politicians online.
However, the firm said the report of comments secretly recorded by Channel 4 News had "grossly misrepresented" Mr Nix's comments.
Before Channel 4 News had broadcast any of the secret filming, Mr Nix told the BBC's Newsnight programme he felt the firm had been "deliberately entrapped".
What does Cambridge Analytica do?
On its website, it says: "Our team of PHD data scientists, expert researchers, and seasoned political operatives have produced decisive results for campaigns and initiatives throughout the world."
It had been credited with helping Donald Trump to presidential victory.
How do I protect my Facebook account?
- Log in to Facebook and visit the App setting page
- Click edit button under Apps, Websites and Plugins
- Disable platform
This will mean that you won't be able to use third-party sites on Facebook and if that is is a step too far, there is a way of limiting the personal information accessible by apps while still using them:
- Log into Facebook's App settings page
- Unclick every category you don't want the app to access, which includes bio, birthday, family, religious views, if you are online, posts on your timeline, activities and interests
There are some others pieces of advice too.
"Never click on a 'like' button on a product service page and if you want to play these games and quizzes, don't log in through Facebook but go directly to the site," said Paul Bernal, a lecturer in Information Technology, Intellectual Property and Media Law in the University of East Anglia School of Law.
Original Source: http://www.bbc.co.uk/news/uk-43480978
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