Facebook finds itself in the midst of another privacy storm, and so once again the issues of data collection and user privacy are back in the headlines. If you're wondering what kinds of information you're giving away to the apps you use – and how you can limit it – here's what you need to know.

We won't go very deeply into the latest Facebook and Cambridge Analytica scandal, because you can read about it elsewhere, and the points we're going to make cover plenty of social media apps besides Facebook. Essentially, the social network stands accused of allowing user data to be collected and used in ways it shouldn't have been, to track and target political opinions.

For its part, Facebook has called the incident "a breach of trust" and says it has already put tighter restrictions in place to stop this from ever happening again. Wherever the blame lies, plenty of us are now reassessing the deal we make when we sign up for services like Facebook, Instagram, and Twitter.

What data do apps hold on me?

The short answer is, an awful lot. Sign up for any free service, from Facebook to Gmail, and you're basically signing away some of your privacy in return for the convenience and features of these free services. It's well worth reading through the privacy policies you can find online – for Apple, Google, Facebook, Instagram, Twitter, Snapchat, and all the others – but you'll notice they often use vague terms. And deliberately so.

You've got two issues to think about. One, what information are these apps collecting about me? Two, how is that data going to be used? Google, for example, logs all your searches and browsing, if you let it – you can see your records here, and switch off some forms of data collection if you like – but also promises not to sell on personal information or let other companies get access to it. It really comes down to how far you trust the companies you've signed up with.

Targeted advertising is the most noticeable way your user activity is going to be turned back against you – that's why you see ads on Twitter, Facebook, Instagram, and Google based on stuff you've already looked at or expressed an interest in. Independent data brokers will often collect up multiple parcels of activity, inside apps and on the web, to build up a pretty comprehensive picture of who you are and what you like.

You may or may not think that relevant adverts are a reasonable price to pay for everything you get from these apps for free – for a long time it's a deal we've all signed up to and accepted. Do you mind if Facebook logs every interaction you make on the site if it means you get a more interesting News Feed, with your favorite people at the top, and products you might actually like down the side?

Then there are the third-party apps you connect up to your Twitter, Facebook, Google, and other accounts, like the personality quiz that apparently harvested so much data for Cambridge Analytica. Again, these apps that connect to your social media accounts will have a data policy and a trade-off between functionality and privacy – either accept the terms, or don't run the app.

Broadly speaking, apps and sites want to track everything you do that can help them learn more about you and throw up better targeted advertising – where you go, what you search for, what you're interested in. The most comprehensive fix is to not make use of these apps at all, though that is a challenge in today's ultra-connected world. If you want to stay connected but keep data collection down to a minimum, we'll talk about that below.

How can I limit the data I share?

Every app you install on your phone asks for permissions. On Android, open up Settings then tap Apps & notifications and choose an app – if you then tap Permissions you can see what the app has access to on your phone. On iOS you need to open Settings, then scroll down and tap an app to see what it has access to.

From these screens you can turn off an app's permission to track your location or to connect to your contacts, for example. Apps will claim they need these details to provide a better user experience – local restaurant recommendations, perhaps – but again, it's down to you how far you trust them, and how comfortable you are with this data being collected.

Keeping the third-party apps that are connected to your social media accounts down to a minimum is a quick and easy way of limiting where your data can go. At least then you've only got to worry what Twitter and Facebook are doing with your data, rather than dozens of other companies – head here for Facebook and here for Twitter and remove any apps you don't recognize or don't regularly use (such as pointless personality quizzes).

Check within each app's settings too: For example, if you tap Settings and privacy on the Twitter app menu, then Privacy and safety, then Personalization and data, you can limit some of the data that's collected – including location data and the other apps on your phone. These steps can limit tracking and data sharing to some extent, but if you really don't want your mobile habits being tracked by an app, uninstall it.

More data is collected on the web, and spending more time logged out of sites such as Facebook and Twitter is one easy way of restricting the amount of data that can be collected as you browse – your browser's incognito or private mode can come in handy here – but of course, once you do sign in and start clicking around on Facebook and Twitter, it's part of the deal you've made that these sites can log that information, and in some cases share it with others.

While these steps do help in limiting certain tracking behaviors, in the end you're agreeing to have Facebook, Google, Twitter, and others track what you do inside their apps, and at the very least sell ads against that activity, in return for using them – it's perhaps time to think about using them less, or at least being more careful about what you do inside these apps and what you share.

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