Want to really know people? Take a look at their Facebook 'likes.'

A new study indicates that Facebook 'likes' say a great deal about a Facebook user. 

It takes half a second – a momentary flick of the wrist and depression of the index finger on the mouse – to "like" something on Facebook. But as a new study from researchers at the University of Cambridge has discovered, viewed in aggregate, all those likes can build a pretty accurate portrait of us as consumers, as Internet users, and as people. 

The study, which was published this week in Proceedings of the National Academy of Sciences, examined the Facebook profiles and likes for 58,466 individuals in the US, and compared that data from information from surveys and personality tests. In many cases, researchers found that using "likes," they could determine the ethnicity of the subject, his or her sexual orientation – and even whether or not someone smoked.

"The model correctly discriminates between homosexual and heterosexual men in 88 percent of cases, African Americans and Caucasian Americans in 95 percent of cases, and between Democrat and Republican in 85 percent of cases," reads the abstract for the article. "For the personality trait 'Openness,' prediction accuracy is close to the test–retest accuracy of a standard personality test." 

In other words, Facebook is as good as old-fashioned personality tests in determining how friendly and outgoing a person you are. 

But the authors of the study caution against reading too much into individual likes. In an interview with CNN, David Stillwell said that building a truly comprehensive portrait required sifting through data from hundreds of likes. In fact, Mr. Stillwell says, the study subjects logged an average of 170 likes. 

"It's like meeting someone for a blind date: If you just ask one question then you can't make an accurate judgment about them. But once you've had an hour-long conversation about their favorite hobbies, interests, brands, and celebrities, then you can start to have some confidence in who they are," Stillwell told CNN. 

All of which is very, very good news for one segment of the population. After all, as the study indicates, Facebook can tell us a great deal about its members – information that can be quickly leveraged by advertisers. 

In related – but by now dated – news, in 2011, an Israeli couple named their third child "Like," after the Facebook feature. Young Like has not yet been reached for comment on the University of Cambridge study. 

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