By Darren Waters
Technology editor, BBC News website
Online search is not a "solved problem", a senior executive for net giant Google has told BBC News.
Google is the world's dominant search engine
"Our position is that search is a very hard problem. We have still a lot of work to do," said Douglas Merrill, who looks after internal engineering.
Google remains the world's most popular search engine but in recent years has expanded activities to include e-mail, instant messaging and online mapping.
Mr Merrill said 70% of the company's activities remained focused on search.
"It is not enough to have the information, the information should be right," said Mr Merrill.
"Sometimes the problem is figuring out what the users mean not what the user said," he added.
Mr Merrill said Google's search focus for the future included better search for mobiles, personalised search, language translation, accessing offline information and defeating web spam.
"Spam is an arms race," said Mr Merrill, adding it was a multi-million dollar industry which was trying to fool search engines.
Unlike spam e-mail, web spam tries to trick search engines into featuring websites selling products such as drugs high up on a list of search results.
The spammers exploit the way search engines work by bombarding blogs and comments pages with links to their websites.
Google prioritises websites in their search results if a particular page is linked to by other sites.
Mr Merrill said: "Spammers are highly motivated. There is a lot of money at stake."
The Google executive said online language translation was important because the company's philosophy was to provide access to "all the world's information".
"We are doing a lot of work in our labs on mechanised translation," he said.
"It (search) should not be stuff in languages we just happen to speak right now."
Mr Merrill said the company pledged never to intermingle search results adverts without clear signposting.
"You should never mix search results and ads because it is dishonest to the user," he explained.
He also defended the company's policy of releasing new services and tools to users before they were finished products.
Tools such as Google Chat and Google Mail are beta products, requiring users to give feedback on problems and suggestions.
"In general we think it is better for our users if we post things in the cloud," he said.
"We launch things and then hear back from the users."
But according to a recent report on the company's track record of new services, Google had yet to attain market leadership in any of its product areas outside search.