The new feature has been described by the company’s founder and chief executive, Mark Zuckerberg, as the site’s “third pillar”, after Timeline and News Feed, who said: “Graph Search is a completely new way for people to get information on Facebook.” The function will initially let users search four categories – people, places, photos, interests – and will gradually expand to cover all content.

The tool has been built for users looking to do their own research on friends or companies, based on specific combined phrases. A limited rollout has begun as a beta product which will expand slowly and be built on over the coming years, evolving in response to how people used it. Zuxkerberg explained: “Graph Search is designed to take a precise query and return to you the answer, not links to other places that might take you to the answer.This is a really big project. It will take years and years to map the whole index of the graph.”

In cases where Graph Search cannot answer a phrase, the service defaults to Microsoft’s web search engine Bing. Zuckerberg reveaked that talks were held with Google about a partnership with Facebook, but the search giant did not agree to Facebook’s privacy requirements, and so the firm went with Microsoft.

Eden Zoller, principal analyst at Ovum, said: “Before the arrival of Facebook’s Graph Search, the search function on Facebook was basic and as such, a wasted opportunity given Facebook’s imperative to strengthen advertising revenues. Facebook Graph Search will no doubt leverage member data to provide advertisers with more targeted, personalised advertising opportunities going forward. But Facebook needs tread very carefully here and be mindful of user privacy. It claims to have built Graph Search with privacy in mind, but Facebook has a mixed track record on this front and is in the habit of pushing privacy to the limits of what is acceptable.

“Facebook Graph Search is not a web search engine, but a search tool designed to enrich the Facebook platform and experience for both users and advertisers. This is sensible as a full blown web search engine from Facebook would inevitably have to compete with Google search, and given Google’s dominance of the search market it would be hard for Facebook to make a serious impact – and win advertising dollars.”