Yahoo! Challenges for Google's Crown

Yahoo! has struck out on its own in the increasingly lucrative web search market by launching its own search engine and ending its relationship with rival Google.

The internet company's decision to launch Yahoo! Search follows its purchase of search provider Inktomi and web advertiser Overture Services in 2003.

Yahoo! had been relying on Google's search technology since June 2000. The $2bn buyout was seen as a sign of Yahoo!'s intention to muscle in on Google's seemingly unimpeachable position as the number one search engine. Microsoft has also signalled its commitment to enter the search engine market as a major rival to both Yahoo! and Google by investing millions in developing its own search technology to use on the MSN.com website.

Jeff Weiner, senior vice-president of Yahoo! search and marketplace, said the move "uniquely positions Yahoo! to change the game in search".

Mr Weiner said "nearly half" of all online searches in the US will be powered by Yahoo! Search Technology once the process of rolling out the new algorithmic search to Yahoo!'s worldwide array of websites is complete - a process that could take several weeks.

"Today's announcement marks the beginning of a rapid succession of innovations from Yahoo! Search that will deliver against our mission of providing the highest quality search experience on the web," Mr Weiner said.

Jonathan Rosenberg, vice-president of product management at Google, told the Reuters news agency: "The transition has obviously been underway for many months. It doesn't come as a surprise."

Yahoo!'s announcement will put extra pressure on Google, which is mulling over a widely-anticipated initial public offering (IPO) of its stock - a move that could raise as much as $20bn, prompting comparisons to net firms' stock offerings during the dotcom boom of the 90s. The cash generated could help Google to fight off Microsoft and Yahoo!'s attempts to grab its slice of the search market.

Google announced earlier this week that had expanded its web index by one billion pages, increasing its total breadth by about one third.