Facebook hopes you’ll use its new social search feature, Graph Search, to find everything from dentists your friends recommend in New York to restaurants they’re talking about in San Francisco. But while the tool appears to be a smart way to glean insights from your connections, it is inherently limited by the amount of useful information shared within a user’s social circle or made publicly available by those outside that circle. That means it may take time—and effort on the part of Facebook users—for it to be truly useful.

Graph Search, which was announced Tuesday and is available to a handful of Facebook’s billion users, allows you to use natural-language terms to quickly search through all the people, places, images, and interests listed in your social network. It also searches publicly available information on Facebook, so a search for “Photos of Paris, France” would show more than just snapshots taken by your friends. And information from the rest of the Web is delivered through a partnership with Microsoft’s Bing search engine.

Because of Facebook’s size and influence, experts say, Graph Search could be a threat to search leader Google and social sharing sites such as Yelp and Foursquare. Yelp’s stock, at least, is already feeling the impact. Its shares fell nearly 8 percent in trading on Tuesday.

Many people have Facebook open in their Web browser all day, so it “seems so easy to just go do a search there,” says Nick Cassimatis, an associate professor in Rensselaer Polytechnic Institute’s cognitive science department and the founder of natural-language search startup SkyPhrase.

However, while there are more than 240 billion photos and a trillion connections on Facebook, Graph Search doesn’t provide access to any new information. It just makes it easier to mine the data you already have access to. Facebook will need its users to help make Graph Search work well—by contributing more “likes,” uploading more photos, and checking in to more places.

Danny Sullivan, editor in chief of the website Search Engine Land, says it “remains to be seen” how well Graph Search will work. Sullivan says encouraging people to contribute more information could be a big challenge, limiting the amount of information Facebook can tap into. If users can’t find what they’re looking for consistently, he says, they won’t use the feature. Graph Search is also limited in that it doesn’t yet incorporate data from Facebook’s Open Graph, which includes information from other Websites and services, such as songs you listen to on Spotify.

Facebook hopes that Graph Search will indeed inspire many users to share more. Speaking on the sidelines of the product’s unveiling Tuesday, Tom Stocky, a director of product at Facebook who helped lead the creation of Graph Search, said users might feel inspired to share more information after using the tool.

Greg Ver Steeg, a computer scientist who studies social networks at the University of Southern California’s Computer Sciences Institute, is skeptical that users will want to spend much time feeding complex queries into Graph Search. “The really successful additions to social media are things that reduce your cognitive load, not add to it—things that make it easier and more automatic to find what you like,” he says.

Graph Search tries to autocomplete queries as Google does, and it includes a number of default search suggestions—”Photos of my friends,” “Restaurants nearby,” “Photos my friends like”—that pop up when a user clicks on the query bar at the top of the home page. While people may try these, Ver Steeg believes most won’t want to exert the effort it takes to type in something more.

If other users do put in the effort, he points out, the results you see will be limited by the size of your social network plus, in some cases, publicly available data. He says this may feel like an artificial limitation when searching for suggestions on things you might like.

Sullivan echoes this concern. “Facebook’s got a big challenge ahead of them,” he says.