How to stop Facebook giving away your personal information

We've all done it, even if we don't want to admit it. Those little quizzes on Facebook that seem so tempting. Maybe it's one that'll tell you which Harry Potter character you're most like. Or perhaps it will tell you the name of the person you'll marry someday. Silly, but all harmless fun, right?

Right?

Brexit and Donald Trump are your fault.

These things are far from harmless. In fact, Brexit and Donald Trump are your fault. That may seem rather harsh, like that school teacher who gave the whole class detention because of one loudmouthed delinquent. But in this case it's a very worrying use of hyper-targeted personal data that carried huge sway in the political arena.

How is this my fault, you swine?

Most people's awareness of the data they give away to these Facebook quizzes is that they'll get your name, email address, probably see the list of things you've liked on Facebook. In return for that you get to do a fun little quiz and share the results.

Unfortunately, that is not, by any stretch of the imagination, all that you give the companies that create the quiz. And just to be clear, the whole reason they create these quizzes in the first place is to get hold of this information. If you've put the information on Facebook, even if it's just being shared with your friends, you are quite likely giving companies access to:

• Your name
• Your profile photo
• Your age and date of birth
• Your current location
• Your home town
• Your job
• Your income bracket
• Your religion
• Your sexual preference
• Your relationship status (including the name and details of your partner)
• Your family (including the name and details of every member of your family)
• Your education level and all of the schools and universities you've attended
• Your current employer
• All of your past employers
• Your political views
• Things you've posted and said on Facebook
• Your interests and hobbies
• Other Facebook apps you've used
• When you're online on Facebook

And here's the big finale:

• All of this information about everyone you're friends with on Facebook

Did you realise that by connecting with someone on Facebook you're giving them permission to pass an incredible amount of personal information on to any marketing company they like? And they probably don't even realise they're doing it.

But isn't this just about advertising?

Personalised adverts may be a little creepy sometimes, but most people find them harmless. But this torrential data leaking goes far beyond advertising.

Have you noticed that 'shock results' in politics are becoming the norm? The vote for the UK to leave the EU and the election of Donald Trump are two very prominent examples. But whatever your politics, this should concern you. Both the Leave and Trump campaigns were underdogs, not expected to win. They both paid a lot of money for online campaigns that can hyper-accurately target specific people based on their backgrounds and beliefs. So what's the battle plan?

• Target your supporters: make them believe that it's a life or death fight, vital to their own survival and wellbeing. Tell them their vote is absolutely vital.
• Target people who oppose you: make them believe your cause is pretty much lost, that it's almost laughable. Tell them it doesn't matter whether they vote or not, because they're safe.
• Target people who support your opponents: use ambiguity and hyperbole to make them doubt if anyone in politics is any good at all. Make them roll their eyes and disengage with the process.

This is creating a bubble around voters. You seal people off into groups who agree with their views. The big picture is lost. People who want change become more likely to act; people who want the status quo become less likely to act.

They have created a tool that allows people to buy political outcomes.

How can I stop this?

By default, Facebook assumes that you're willing to share everything you put online with everyone. But you can change that. Of course, Facebook doesn't make it all that easy to find where to do it.

HINT: if you're in a hurry, try Option Three.

OPTION ONE: The Nuclear Option

No, not suggesting you delete your Facebook account. But you can turn off any access to third party apps, which will make sure your data is only shared with the people you're actually friends with, not with data-mining companies. The downside is that you won't be able to use apps, games & quizzes on Facebook, or log in to other websites using that handy 'Login with Facebook' button. How important that is is entirely up to you.

1. In the top-right dropdown menu on Facebook (with the down arrow), click Settings.
2. In the left sidebar, click Apps.
3. In the Apps, Websites and Plug-ins box, click Edit.
4. A box will open explaining what disabling Platform will do. If you want to go ahead, click Disable Platform.

Option Two: The Painstaking Option

If you like using Facebook apps, then you can go through and set what you share with each one individually. This gives you a lot of control over what you share, but can take a long time if you use a lot of apps that connect to Facebook.

1. In the top-right dropdown menu on Facebook (with the down arrow), click Settings.
2. In the left sidebar, click Apps.
3. In the top 'Logged in with Facebook' box, you'll see all of the apps that you've connected to Facebook. You'll recognise some, but some will probably have been pushed out of your memory into the mists of time before 2012.
4. Click on each app to see what you're sharing with them and what you're allowing them to do. You can turn off things that you no longer want to share.

Option Three: The 'I don't trust my Friends' option

A quicker way to get back some control is to prevent people you've connected with sharing your data by using apps and quizzes.

1. In the top-right dropdown menu on Facebook (with the down arrow), click Settings.
2. In the left sidebar, click Apps.
3. In the 'Apps others use' box, click Edit.
4. A box will appear with some categories of personal information. You can uncheck the tickboxes to stop this information being shared by your friends.

Note that this method can't stop ALL sharing. Basic information about you and your friends list is always shared, along with anything you've set as 'public' when you created it.