Yahoo! is to launch its social search service in the UK, marking the event with a huge advertising campaign.

The company's Yahoo! Answers service already serves 50 million users with customised answers, allowing individuals to tap others' personal knowledge to help resolve queries.

To celebrate its launch in Britain, Yahoo! Answers is to be the subject of a major marketing campaign across the country, featuring TV and radio spots as well as billboard advertising.

In addition, one celebrity will ask a question to Yahoo!'s throngs of users each week for a month and a half.

"This is the biggest campaign that Yahoo! have mounted for five or six years," Stephen Taylor, Yahoo! Europe's head of search, told the Guardian. "It's a measure of the confidence we have in Yahoo! Answers."

Mr Taylor added that Yahoo! Answers may be eventually combined into conventional non-human search results, bringing the two alongside each other on its main portal.

"We do see our core internet search and social search getting closer and closer together," he continued. "Essentially, what you are building is a global knowledge database."