Tom Stocky wants to tell you what people think about things that are happening around the world right now. It sounds a lot like the mission of Twitter, but Stocky works for Facebook, tackling a problem the company has continually struggled with: search.

There are 1.5 billion searches a day on Facebook, but the vast majority are for people's names—the kind of search one might surreptitiously conduct after meeting an alluring stranger in a bar. Last October, the company quietly made it possible to search for all public posts on Facebook, not just material posted by friends or pages. Stocky's team developed the new function, which uses an algorithm to rank and refine trillions of posts from Facebook users. "What we really tried to do was make Facebook a place where you could tap into the global conversation of what was happening in the world," Stocky said at Facebook's Menlo Park, California, headquarters, unwittingly (or perhaps not) trotting out a favorite phrase of executives at rival Twitter. "We really want to basically make Facebook the best place to find what people are saying about something right now."

A usable search tool on Facebook could have big implications for the social network. People might rush to restrict their privacy settings once they understand that their posts are discoverable by anyone. Or they could scramble toward the limelight, crafting timely posts for a mass audience and giving the social network into the kind of topical and pulse-quickening timeline currently featured by Twitter. It could be Twitter, but with 1.6 billion users instead of 320 million. It could be Google, but personalized and populated by friends.

"If search on Facebook really takes off, I think Google is under pressure," said Victor Anthony, an analyst at Axiom Capital Management. "If they get it right and they're able to monetize against searches, it's extremely lucrative for Facebook—billions in revenue."

But first, there's a lot to get right.

Search was one of the first features Chief Executive Officer Mark Zuckerberg built for Facebook when he started it at Harvard in 2004. Those first college students could have a profile, and they could search for friends to add—and that was it. Throughout the years, Facebook has made some moves to enhance the search bar that it prominently placed on the top of the page, but for the most part, it languished.

"When people actually associate Facebook with answering the questions they have, that's when we'll be successful."

In 2010, the company made a deal to let Microsoft show its Bing Web results there. A couple years later, Facebook made an attempt at its own social database crawler, which it earnestly dubbed Graph Search. Zuckerberg introduced the product at a press conference in January 2013. It required users to enter queries in a highly stylized way, as if they were talking to a robot: "My friends who went to high school in Long Island and live in Philadelphia" or "Google employees who like national parks." Not surprisingly, it never caught on. A year later, Zuckerberg admitted to Bloomberg that Graph Search didn't work as intended even half the time.