That's because, according to a January 15th, 2013 Mashable post, Facebook is about to make it a lot easier for people who you've allowed to access info about you (e.g., anything that is "Public" on your Facebook profile) to "unearth previously hidden or hard-to find information."
As described by Mashable, Graph Search does NOT involve a change in user privacy settings - but it's likely many users will be surprised when data that they have (unwittingly?) shared becomes more accessible and useful to people with something to sell: "People will be able to use Graph Search to find any content that you already share with them. Uploaded some public, geo-tagged photos of the Empire State Building? They're Graph Searchable by anyone and everyone. Like "Toy Story 3?" If your likes are public, that like is Graph Searchable by all. Checked-in to Golden Gate Park, but you have your privacy set so only friends can see your check-ins? That's Graph Searchable, but only by your friends. And so on."
How long before some enterprising indie filmmaker starts using the information from Facebook's Graph Search to reach out to people who've publicly shared information on Facebook (potential fans?) to market a film?
"According to Facebook’s promotional video and CEO Mark Zuckerberg’s presentation, you can type in real-world, real-language questions you might ask for instant and useful answers."