Facebook set to be grilled by lawmakers over Trump-linked data firm

Cambridge Analytica is the name on everyone's lips right now, and British and U.S. lawmakers want to know about Facebook's dealings with it.

The U.K. based political data firm has been suspended by Facebook, following revelations it used the personal data of 50 million users without their knowledge.

Cambridge Analytica allegedly used this data for something it called "psychographic profiling," using the information to predict voting behaviour. It was used by the Trump campaign during the 2016 presidential election, and is being investigated for its role in the "Brexit" referendum vote.

Now British lawmakers will order Facebook to explain why it hadn't been straight up about its relationship with Cambridge Analytica.

At the end of 2015, Facebook had reportedly asked the data firm to delete all of the personal information it misappropriated, but according to recent reports by The New York Times and The Guardian, not all of that data was removed.

"I will be writing to Mark Zuckerberg asking that either he, or another senior executive from the company, appear to give evidence in front of the Committee as part our inquiry," Damian Collins, chair of the UK parliament's media and culture committee, said in a statement.

"It is not acceptable that they have previously sent witnesses who seek to avoid asking difficult questions by claiming not to know the answers. This also creates a false reassurance that Facebook's stated policies are always robust and effectively policed."

Republican senator Jeff Flake also slammed the breach on CNN's State of the Union, especially in light of investigations over Russia's involvement in the last U.S. presidential election.

"This is a big deal, when you have that amount of data," Flake said. "And the privacy violations there are significant. So, the question is, who knew it? When did they know it? How long did this go on? And what happens to that data now?"

Massachusetts attorney general Maura Healey said on Twitter the state would be opening an investigation into Facebook.

This Tweet is currently unavailable. It might be loading or has been removed.

So how did Cambridge Analytica manage to get its hands on all that data? Facebook has noted the firm extracted data from users taking personality quizzes, initially through an app called "thisisyourdigitalife," where people were prompted to give out their personal information in a few simple taps. How exactly did this seemingly innocent activity lead to unauthorised access of 50 million user accounts? We've broken it all down here.

Amid all this, there's never been a better time to check out which random apps and quizzes have access to your Facebook data.