Traditional search tools would not do the trick, Rasmussen says. "Using traditional information-retrieval systems to mix keyword and structured queries is fairly well understood," he writes. But Graph Search needs to be able to return results that are more than just a single connection away, he says. And then there's the whole privacy angle. Engineers were able to design a system that combs through the data, but users have in many cases created explicit restrictions on who can see that information. Graph Search needs to ensure that it only creates results that have been shared with the searcher. The more complex the search query, the bigger the challenge is to ensure that whoever is searching does not see something they're not supposed to.
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And that's basically where Graph Search is today. Facebook officials have stressed that Graph Search is still very young. It's only open to select users - there's already a waiting list you can request to be on - and Graph Search only searches people, photos, places and interests. It's not yet available on mobile devices, nor in languages other than English. It's also not searching timeline posts and comments - by far the biggest dataset for Graph Search, Facebook says.
Facebook is betting big on Graph Search though, even calling it the third pillar of the social network. In an article about Graph Search that came out the same hour Facebook announced the tool, Wired reporter Steven Levy notes that in Graph Search, the Facebook logo is replaced with an F - the search toolbar actually kicked Facebook's name off its own network. A patent Facebook received in November 2012 could be Facebook's signal that it has bet heavily on Graph Search as being a major initiative for the company.
Levy writes that Graph Search is "fundamentally different from web search." Because of the trove of data Facebook has about users, "we can answer a set of questions that no one else can really answer," Zuckerberg told Wired. Levy, the Wired author, notes that "nobody has feared this day more than Google, which suddenly faces a competitor able to index tons of data that Google's own search engine can't access."
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Facebook engineering manager Kari Lee explains in a video announcing Graph Search: "In web search it's very often the case that if you do a search for apple and I do search for apple, that we'll basically get the same results," she says. "On Facebook, when you do the same searches, you get completely different results because of the depth of personalization we do."