SAN FRANCISCO — Facebook’s greatest triumph has been to persuade a seventh of the world’s population to share their personal lives online.
Now the social network is taking on its archrival, Google, with a search tool to mine that personal information, just as people are growing more cautious about sharing on the Internet and even occasionally removing what they have already put up.
Whether Facebook’s more than one billion users will continue to divulge even more private details will determine whether so-called social search is the next step in how we navigate the online world. It will also determine whether Facebook has found a business model that will make it a lot of money.
“There’s a big potential upside for both Facebook and users, but getting people to change their behaviors in relation to what they share will not be easy,” said Andrew T. Stephen, who teaches marketing at the University of Pittsburgh and studies consumer behavior on online social networks.
This week, Facebook unveiled its search tool, which it calls graph search, a reference to the network of friends its users have created. The company’s algorithms will filter search results for each person, ranking the friends and brands that it thinks a user would trust the most. At first, it will mine users’ interests, photos, check-ins and “likes,” but later it will search through other information, including status updates.
“While the usefulness of graph search increases as people share more about their favorite restaurants, music and other interests, the product doesn’t hinge on this,” a Facebook spokesman, Jonathan Thaw, said.
Nevertheless, the company engineers who created the tool — former Google employees — say that the project will not reach its full potential if Facebook data is “sparse,” as they call it. But the company is confident people will share more data, be it the movies they watch, the dentists they trust or the meals that make their mouths water.
The things people declare on Facebook will be useful, when someone searches for those interests, Tom Stocky, one of the creators of Facebook search, said in an interview this week. Conversely, by liking more things, he said, people will become more useful in the eyes of their friends.
“You might be inclined to ‘like’ what you like so when your friends search, they’ll find it,” he said. “I probably would never have liked my dentist on Facebook before, but now I do because it’s a way of letting my friends know.”
Mr. Stocky offered these examples of how more information may be desirable: A single man may want to be discovered when a friend of a friend is searching for eligible bachelors in San Francisco or a restaurant that stays open late may want to be found by a night owl.
“People have shared all this great stuff on Facebook,” Mr. Stocky said. “It’s latent value. We wanted a way to unlock that.”
Independent studies suggest that Facebook users are becoming more careful about how much they reveal online, especially since educators and employers typically scour Facebook profiles.
A Northwestern University survey of 500 young adults in the summer of 2012 found that the majority avoided posting status updates because they were concerned about who would see them. The study also found that many had deleted or blocked contacts from seeing their profiles and nearly two-thirds had untagged themselves from a photo, post or check-in.
“These behavioral patterns seem to suggest that many young adults are less keen on sharing at least certain details about their lives rather than more,” said Eszter Hargittai, an associate professor of communication studies at Northwestern, who led the yet unpublished study among men and women aged 21 and 22.
Also last year, the Pew Internet Center found that social network users, including those on Facebook, were more aggressively pruning their profiles — untagging photos, removing friends and deleting comments.
