Mark Zuckerberg's dreaded homework assignments

Over two days, almost 10 hours.

If you watched every moment of Mark Zuckerberg’s testimony in front of Congress this week, you’ll know he rolled out one phrase an awful lot: “I’ll have my team get back to you.”

Now some of these were bits of data Mr Zuckerberg simply didn’t have to hand - such as why a specific advertisement for a political candidate in Michigan didn’t get approved.

Other follow ups, though, will require some hard graft from his team. What they produce could provide even more negative headlines for the company, as it is forced to divulge more of its inner workings than it has ever felt comfortable with.

Looking through the transcripts, I’ve counted more than 20 instances where Mr Zuckerberg promised to get back to representatives with more information. But these are the assignments I think could cause the company the most headaches - and provide some revealing answers.

1) Data on non-users

Set by: Congressman Ben Lujan (Democrat, New Mexico)

"You’ve said everyone controls their data, but you’re collecting data on people who are not even Facebook users who have never signed a consent, a privacy agreement.”

Dubbed “shadow” profiles, details of exactly what Facebook gathers on people who haven’t even signed up to the service has been always been a bit of mystery.

Even, apparently, to Mr Zuckerberg himself. He testified that he didn’t know the term, but acknowledged the firm did monitor non-users for “security” purposes.

Mr Zuckerberg promised to share more details on what data is gathered on people who don’t sign up for Facebook, as well as a full breakdown of how many data points it has on those who do.

In a related request, Mr Zuckerberg will provide details on how users are tracked (on all their devices) when they are logged out of Facebook.

2) Moving to opt-in, not opt-out

Set by: Congressman Frank Pallone (Democrat, New Jersey)

"I think you should make that commitment.”

Creating new regulation will be an arduous, flawed process. But one thing Facebook could do right now? Move to an opt-in model, one which requires users to decide to make something public, as is the default (and most popular) option for posting content now.

In a similar vein, Mr Zuckerberg was asked to get back to Congressman Frank Pallone on how the company might consider collecting less information on its users.

3) Repercussions for censorship mistakes

Set by: Congressman Steve Scalise (Republican, Louisiana)

"Was there a directive to put a bias in [the algorithms]? And, first, are you aware of this bias that many people have looked at and analysed and seen?”

One surprising admission made by Mr Zuckerberg before these hearings was that despite acknowledging the company made big mistakes, nobody has been fired over the Cambridge Analytica affair.

Representative Steve Scalise wants to take questions on accountability a step further.

In cases where Facebook reverses a decision to remove content - i.e. admitting it over-moderated - what kind of repercussions did those responsible face? If someone created an algorithm that unfairly filtered certain political views, was there any kind of punishment?

4) Specific rules for minors

Set by: Senator Ed Markey (Democrat, Massachusetts)

"We're leaving these children to the most rapacious commercial predators in the country who will exploit these children unless we absolutely have a law on the books.”

On Facebook the minimum age of users is 13, not counting the company’s Messenger for Kids app (which doesn’t collect the type of data Facebook’s main app does).

But for those aged 13-18, or maybe 21, what happens in those oh-so-delicate years should be protected by tighter rules, Senator Ed Markey suggested.

Mr Zuckerberg said the idea “deserved a lot of discussion”, but maybe not a new law. He promised to get his team to “flesh out the details”.

5) How many ‘like’ and ‘share’ buttons are out there?

Set by: Congresswoman Debbie Dingell (Democrat, Michigan)

“It doesn't matter whether you have a Facebook account. Through those tools, Facebook is able to collect information from all of us."

It seems like everywhere you look there is a button prompting you to “like” or share things on Facebook - indeed, there’s one on the page you’re reading right now.

A request to at least estimate how many of Facebook’s buttons are out there might at first seem like an abstract demand - but the response could be quite something.

The “like" buttons enable Facebook to track users on pages that are not part of Facebook itself, providing more data for advertisers.

If it’s even possible to tot up how many buttons are out there on the web, expect a number in the hundreds of millions - that’s hundreds of millions of pages with which Facebook is tracking your activity beyond its own borders.