Way back in January, Facebook started to roll out Graph Search, a clever way to filter through your friends' posts to find specific content. It's still in beta phase and hasn't been rolled out to everyone as yet, allowing the development team time to work out the kinks in the system.
Graph Search is built on semantic search. In other words, the algorithms used not only search what you type, but they interpret your request by context and search for what they think you mean. Sometimes semantic search is accurate and provides enlightening results, other times not so much. Think of when you search using Google. When I recently typed "Why" in the search box, Google guessed the rest of my question would be "…is the sky blue", "…am I so tired", "…did the pope resign", and "…do cats purr." Clearly Google doesn't know me as well as it thinks, since I'm not really a weary, contemplative Catholic who is interested in cats, but based on previous queries, Google made some assumptions.
In an introductory video, Facebook emphasizes the "depth of personalization" Graph Search provides. Just like your newsfeed is personalized, Graph Search is too. The Graph Search introduction page on Facebook explains how it works by using a search for "photos of Tokyo." Your results will show public photos of Tokyo but also photos your friends have posted. No two people have identical friends' lists, so no two searches will show the same results.
One caution is that photos of you may show up in a public search if the location has been tagged. In other words, if you're in those photos of Tokyo that were used in the previous example, you have no control over who will see them.
One feature with great potential is the ability to sort through search results and reviews to get to the ones that really matter. Sites like Urbanspoon allow users to post ratings of restaurants, giving you an idea of what the food is like, if it's a good value, or whether the service is any good. But if you don't know "ThaiFoodLuver66," how do you know if his opinion matters? What if he hates every restaurant? With Graph Search, you can weed out the opinions of friends who've steered you wrong and get to the opinions of those that matter to you the most.
Restrict "Who can look me up?" to just Friends.
Don't let search engines link to your Timeline.
Review all of your posts and things you're tagged in.
Limit who can see your future posts.
Graph Search will no doubt show up in the news as more and more Facebook users gain access. As with any new feature, the key is to educate yourself, take the time to protect your privacy, then explore.