I am using it on my profile already and for me it's actually good. Nice to see Facebook made a systematized way of searching in their network.
i think you might be able to search for lets say "age 22 to 30, single, who lives near san diego". i think i might find someone interesting.
Facebook's Graph Search both has positive and negative effects. Let's take a look on the Positive aspect first. Through this innovation, it could help people connect with others to whom they have a same interest with. And this could help businessmen/marketers to profile their target consumers. However, on the Negative aspect, it might intrude the privacy of an individual. The idea of "private info" might fall into "non-sense." My take is, social media, as it is, is a border less world. We can't "totally control" what will happen. But please it is in the hands of each one of us to be responsible.