Facebook users' online behaviour reveals intimate details about their personality which could allow strangers to predict their sexuality, political views and religion, researchers say.
Experts say that by studying "likes" - the system used to show approval on the social networking site - it is possible to accurately predict what a person is like in real life.
Whether it is drug users being more inclined to show approval for Big Momma's movies or people with high IQ showing a taste for curly fries, the patterns are not always immediately obvious to the untrained eye.
Michal Kosinski, operation director at the University of Cambridge's Psychometrics Centre, said: "We believe that our results, while based on Facebook Likes, apply to a wider range of online behaviours.
"Similar predictions could be made from all manner of digital data, with this kind of secondary 'inference' made with remarkable accuracy - statistically predicting sensitive information people might not want revealed.
"Given the variety of digital traces people leave behind, it's becoming increasingly difficult for individuals to control."
Instagram Lets The Cat Out Of The Bag
FourSquare was designed to show the world your location -- but sometimes <a href="http://www.huffingtonpost.com/news/instagram">photo-sharing app Instagram</a> inadvertently gives us away. In fact, we're so accustomed to snapping "artsy" pics of puppies and salads that it's possible we're unintentionally sharing our whereabouts, particularly if the photos aren't categorized as "private." So if you call out of work sick, make sure you don't accidentally post a picture of yourself relaxing at the local beach. Or, to minimize unwanted attention, go to your Instagram "Options" page and select the "Photos Are Private" button.
If You See Something, Type Something?
For many years, we were able to read Facebook messages at our leisure -- and then promptly ignore them. Now, <a href="http://newsroom.fb.com/News/434/A-New-Look-for-Facebook-Messages">after a Facebook update this summer</a>, users can see when someone has read a chat or message they've sent. So if you want to avoid the awkward realization you've ignored someone, type a message back, don't open the message to begin with, or use this <a href="http://crossrider.com/install/14917-chat-undetected">Chat Undected extension</a> to regain your excuse for not responding.
Whoops, We Stalked You (And You Know It)
<a href="http://www.huffingtonpost.com/news/okcupid">OkCupid</a> and <a href="http://www.huffingtonpost.com/news/linkedin">LinkedIn</a> are used for notably different purposes, but these social networking sites share a (potentially embarrassing) feature. Both platforms show who has viewed your profile and when you're checking out someone else's, making "cyber stalking" a not-so-anonymous act. In order to privately dig into another person's information, both websites offer memberships, which will cost you a few extra bucks a month. But then, of course, you'll be able to check out as many profiles as you want, without ever being detected. Creepy? No, we find it more... <em>practical.</em>
Facebook Bares It All
Everyday we might read a few news articles online, "Like" a slew of photos on Instagram or listen to a couple tunes via Spotify. All of the above activities now have "<a href="http://www.huffingtonpost.com/2012/01/20/facebook-frictionless-apps_n_1213970.html">frictionless Facebook apps,</a>" or apps that automatically post activities to your Facebook profile without the use of a manual "share" button. Every app has different preferences, so be sure to read the details of what you're allowing Facebook to publish. We know for a fact that nothing is worse than accidentally publishing a video titled "ToPLeSs CHiCkS" to your profile, or telling the world that you read a heinously embarrassing "news" article about <a href="http://www.huffingtonpost.com/2012/05/22/miley-cyrus-side-boob-actress-sex-scenes-losing-virginity_n_1536026.html">some celeb's sideboob</a>.
The World Knows Where You Walk And Where You Talk
Sometimes we want people to know our location. But have you ever forgotten to turn off Twitter's geo-tweeting feature, which specifies your exact location, only to find you've been leaving a digital footprint for all the world to see? <a href="http://www.huffingtonpost.com/2011/03/07/what-not-to-post-on-twitter_n_829903.html#s245051&title=Confessionals_Office_Gossip">Be weary of oversharing</a> information. Twitter is an open website, so anyone can Google your name to find your Twitter handle. If you want to limit who can see your profile, go to Twitter's "Settings" page and check the "Protect my Tweets" box, or turn the location feature off (seen in the image to the left).
Facebook 'Pages' Are Actually Advertisements
Occasionally, companies will offer customers rewards for "Liking" their brand on Facebook. You might be a sucker for incentives, but don't forget -- once you "Like" an <a href="https://www.facebook.com/FacebookPages">organization's Page</a>, you'll receive corporate updates that have the potential to litter your News Feed. So "Like" accordingly!
Are You Talking To Me?
When was the last time you checked you're <a href="https://www.facebook.com/help/188872764494245/">"Other" Messages</a> on Facebook? This hidden folder displayed in the top left corner of the Messages screen holds posts from people you're not connected with on Facebook. But who remember to look there? Not us... The same rings true for Direct Messages on Twitter, or InMail on LinkedIn. While these modes of communication can be awesome resources... sometimes we forget they exist.
The study, based on the Facebook profiles of 58,000 people in the US, found that online behaviour can be used to make surprising accurate predictions about users' race, age, IQ, sexuality, personality, substance use and political views.
After feeding Facebook preferences into an algorithm, they created models which were able to determine male sexuality with 88% accuracy, race with 95% accuracy, political leanings with 85% accuracy and religion 82% of the time.
But few users clicked "likes" which explicitly revealed these traits.
For example, fewer than 5% of gay users clicked obvious links such as "Gay Marriage" and instead inference were drawn from more popular likes such a music and TV shows.
The finding could be used to direct personalised marketing to web users but also highlights potential threats to privacy.
Kosinski said: "I am a great fan and active user of new amazing technologies, including Facebook.
"I appreciate automated book recommendations, or Facebook selecting the most relevant stories for my newsfeed.
"However, I can imagine situations in which the same data and technology is used to predict political views or sexual orientation, posing threats to freedom or even life.
"Just the possibility of this happening could deter people from using digital technologies and diminish trust between individuals and institutions."