SOCIAL media giant Facebook today announced at a "mystery event" that it is creating its own search engine.
Zuckerberg, 28, stressed that the new product was "very, very different" to web search engines offered by other tech giants such as Google because it only looks for data on Facebook itself.
It will allow users to search for people, photos, places and other content that has already been shared on the social network.
The announcement came after fevered speculation over what would be unveiled at today's "come see what we're building" presentation.
Some reports had suggested Facebook - which has one billion users worldwide - would be moving into hardware with a smartphone or tablet product of its own.
Other commentators had suggested that Facebook would announce a charge for sending messages to users, an overhaul of its news feed feature or a new advertising network.
Zuckerberg said the new search tool would be rolled out "very slowly", starting with a beta version available to a limited number of users from today.
"This is one of the coolest things we have done in a while," he said, adding: "Graph Search is the kind of product that we love to build at Facebook - it's a big technology problem and it's also a big social problem.
"It's a kind of problem that Facebook and our culture are uniquely suited to build."
Although he repeatedly stressed the new service was different from a web search, Zuckerberg said Graph Search would be "integrated" with Microsoft's Bing search engine.
Searches that are not "mapped out" by Graph Search will be redirected to Bing, under an agreement between Facebook and Microsoft.
Asked whether this targeted Google, Zuckerberg said: "You know, I would love to work with Google - when we did our Bing web search integration we were very public about the fact this wasn't something we were trying to do with Bing.
"We want to make web search social in general."