So Big Brother could be watching us, through Facebook.

In case you hadn't heard, Cambridge University has devised a statistical model that can apparently work out people's sexual orientation, religious beliefs, political views, IQ level and even drug use, with a high degree of accuracy, just by analysing their Facebook likes. Like Harley Davidson motorbikes? Then you have a low IQ. Jennifer Lopez? You're an extrovert. Wicked the Musical? If you're a man, you must be gay. Every time you click the thumbs-up button on Facebook, you are apparently revealing a bit more about yourself, information that faceless corporations can use to target you with advertising and unscrupulous governments could use to persecute you. As one privacy campaigner has warned: "We need to fundamentally re-think how much data we are voluntarily sharing."

That sort of reaction is inevitable, given how many people worldwide use Facebook (one billion on the last count), but should we really be concerned we're in the clutches of an invisible puppetmaster? I don't think so.

This latest research is both unsurprising and nonsensical. It should come as no surprise to anyone that indicating their likes and dislikes on Facebook helps others to form an idea about who they are. We all share information about ourselves all the time, from the way we dress to the way we talk to our likes and interests, as a way of projecting ourselves. We do it without thinking about it. A woman sitting in a cafe with her hair in dreadlocks, wearing ethnic clothes and reading Sylvia Plath, is unlikely to be mistaken for a stalwart of the local Conservative Association, and probably wouldn't want to be.

At the same time, the diversity of humanity and the unfailing capacity of human beings to defy easy categorisation makes any kind of profiling highly fallible. There are always so many exceptions to the rules. "Vegetarian, loves animals and comic films," it's doubtful that information would have flushed out Hitler. "Likes cats, and arts and crafts," you'd never guess the person in question – someone I know – is a seasoned outdoorsman who traps his own dinner. And here's a lovely irony: there's a Facebook page called "Straight Guys Who Like Musicals and Plays". It has 530 likes.

While the Cambridge University model was 95% accurate at telling if someone was black or white, it was only 73% accurate at telling if someone took illegal drugs and only 60% accurate at working out if someone's parents had split up when they were young.

Computer software can never see into your soul. While Big Brother could glean some information about you from your Facebook page, you could easily hoodwink him with a few strategic red herrings. Alongside your love of Plath or Oscar Wilde (signs, apparently, you are liberal and artistic), you could add that you liked the film Monster-in-Law (an indicator of inherent conservatism). It would be like dreadlocked Plath girl finishing her book and getting out a copy of the Daily Mail.

You can't trust what people say on Facebook in any case, since people use their likes to project a certain public image that might be wildly at odds with reality, much like when people name-drop writers they've never read. In any case, some of the profilers' assumptions are clearly bonkers, such as how liking Usain Bolt means you must be single or liking curly fries means you are intelligent. These could be simple coincidences (and I'm not just saying that because I don't like curly fries).

You can see why Michal Kosinski, the scientist behind the analysis, fears his techniques could be abused by oppressive regimes to persecute gay people or political opponents. Dictators are not known for their commitment to a high standard of evidence. For those of us lucky enough to be living in stable democracies, part of the privilege of freedom is being able to be who we are, openly and without paranoia. So we might get a few more adverts targeted at us. It's not the end of the world, so long as the adverts aren't for curly fries.