Even discreet Facebook users are often giving away far more than they would ever have imagined to the social network.
Simply selecting the wrong option in one of Facebook’s menus can mean you are broacasting your location to the entire world - and Facebook ‘Likes’ are a minefield.
A research team used information from a questionnaire filled in by 86,000 people, and compared it with their Facebook likes.
They found that just 100 Facebook ‘Likes’ was enough to reveal crucial details about a person’s personality – information which could be highly valuable to advertisers and even potential employers.
‘There’s a very big dark side to the technology,’ researcher Michael Kosinki at Stanford said.
‘With one click of the button it could be applied to the entire population of the world.’
Below are five things Facebook already ‘knows’ about you - and what to do if you’re alarmed...
Facebook knows if you’re straight or gay
A University of Cambridge study found that it’s possible to guess a person’s sexuality with a high degree of accuracy, based simply on their Facebook ‘Likes’.
This isn’t a case of people liking, say, topless models of the opposite sex if they’re straight - it’’s a more complex process where a computer algorithm compares your ‘Likes’ with typical choices for certain groups, such as male straight people, or female gay people, and makes a guess.
If this is information you would rather Facebook DIDN’T know, visit your ‘Likes’ page (on your Activity Log) and get rid of as many as you can.
Facebook knows where you’ve been
If you’ve ever used the Facebook feature ‘Nearby Friends’, Facebook will store a record of exactly where you’ve been, using your smart device’s GPS or Wi-Fi location services.
It will also broadcast your approximate location to anybody else on your Friends list who has the feature enabled - which, as you have no way of controlling this, could be anyone.
If enabled, they will see your approximate loction on a map within Nearby Friends in the Facebook app.
The feature can be disabled, though: Facebook’s instructions on how to do so can be found here.
Facebook knows who you’ve been stalking
If you’ve ever repeatedly searched for a person’s name, Facebook will remember and store this information - and the next time you search when logged in, it will predict your most common searhes.
This data can be quite private - and embarrassing.
For instance, if you’ve searched repeatedly for a specific person, this can be very obvious, even if someone happens to glance over your shoulder as you use the site, as the function will auto-suggest the names you’ve searched for most frequently.
Thankfully, it’s possible to delete this data entirely within your Facebook settings. Go to Activity Log (one of the options at the top of your Profile page), then select More, then Search.
From this page, you’ll be given options to delete either individual searches, or your entire search history. By default, Facebook stores this data, and it’s available to anyone who sits down at a PC logged into your account.
Facebook can tell your employer if you’re a reliable worker
Facebook can work out which broad personality ‘type’ you fall into - and that data can be easily discovered by anyone with access to a list of your Facebook ‘Likes’.
That could include potential employers - as, depending on your privacy settings, the data could be available to anyone who searches your name within Facebook.
A University of Cambridge team used information from a questionnaire filled in by 86,000 people, and compared it with their Facebook likes.
They found that just 100 Facebook ‘Likes’ was enough to reveal crucial details about a person’s personality – information which could be valuable.
Experts suggest that the info could even be used by employers to predict people’s personalities while screening them for jobs.
Facebook knows every website you’ve visited
Like Google, Facebook stores a record of every site you’ve visited - and it’s not deleted when you clear your browser’s history.
In the case of Facebook, this history is not visible - but Facebook stores the data, and uses it to serve adverts to you within Facebook.
This has the potential to be embarrassing.
If you need to be private, don’t log in to services such as Google or Facebook. Browser plug-ins such as Click&Clean offer tools to check whether you are logged in to services such as Facebook, which might log your activities online, before browsing.