Google has long been the king of search, dominating rivals including Yahoo Inc. and Microsoft Corp. But it increasingly sees social networks such as Facebook as challengers to its search engine, a company official said Monday.

As people search out advice online for everyday, personal decisions, the standard list of links served up by Google is not seen as intimate or trustworthy. For decisions such as choosing a restaurant or a day-care provider, social networking sites or known review sites have an advantage, said Google group product manager Ken Tokusei.

Such sites offer information from friends or acquaintances, and Tokusei said users tend to trust that information more. This puts Google's results at a disadvantage.

"We haven't gotten to the point where results are seen as if they come from someone you know," said Tokusei.

The search giant has begun to offer tools for users to rate results and delete unrelated links, but it still has work to do, he said.

Users expect better answers

As internet users gain savvy and experience, they also expect better-honed answers to queries. Sites such as WolframAlpha, launched earlier this month, comb the internet for data, and analyze it to provide specific answers to queries, rather than a list of sites.

Google Inc. does something similar for some searches, providing price quotes for "Sony stock" or an answer for "Tunisia capital." But it also provides the familiar list of sites to dig further, a strategy it is unlikely to change.

"It's a matter of determining what kind of information the user is looking for. But we will always serve some links to pages with our results," said Tokusei.

He spoke to reporters at Google's Japanese headquarters in Tokyo on Monday, where he gave an overview of the company's basic search tools.

Google has developed a host of expanding tools and services, from a mobile operating system to an online word processor, but it devotes 70 per cent of its employees and resources to search.

The company still faces fresh competition from its traditional rivals, which are regrouping in an attempt to take back market share.

Microsoft has failed to make much headway in repeated internet ventures. But the deep-pocketed company, which has poured hundreds of millions of dollars into improving its search engine, continues to develop a new search technology, part of which is called "Kumo" internally.

Yahoo, which has seen its market share plummet to Google, is tweaking its search results, cutting out some links and emphasizing images and video.

Microsoft chief executive Steve Ballmer has said he is still interested in buying part of Yahoo, after a proposed deal was turned down last year.