The Cambridge study says it was easy to draw "inferences" from likes. For example, while only 5% of gay users directly clicked on "gay marriage" as a like, a majority of users could be identified as gay by likes regarding cultural themes such as movies, music and television shows. That's valuable information for political campaigns and media advertisers, Cambridge researchers say. The research also revealed some unique personal attributes. Who knew curly fries were linked to a high I.Q., or that smokers are more afraid of spiders than non-smokers? Until now, we're guessing nobody. The study concludes by saying Facebook likes are a huge privacy issue, so users had better be careful about their online preferences. "I am a great fan and active user of new amazing technologies, including Facebook," says Michal Kosinski, operations director at the university's Psychometric Centre, who conducted the research with his Cambridge colleague David Stillwell, along with Thore Graepel from Microsoft Research ( MSFT). "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 -- hampering technological and economic progress," he adds. "Users need to be provided with transparency and control over their information." Stopping strangers from building a personal profile without your permission isn't too tricky. Simply stop liking so many things on Facebook, or at least throw online trackers off the trail by liking things you, well, don't like. It may seem a bit silly, but make no mistake, what you like on Facebook can lead to some negative consequences at best and vulnerability to online predators at worst.