Engine interprets search results to allow for better ranking.
Yahoo has expanded its oneSearch mobile offering to all device users.
The offering was previously bundled with the Yahoo Go for Mobile application that is available on a limited number of handsets only.
Yahoo makes an attempt to interpret search queries by offering results that are grouped. A search for a name, for instance, offers news articles, websites, special mobile sites, web images and Flickr photos.
The results for a restaurant search offer links to a listing for the company, as well as business categories and web and mobile web results.
Mobile internet and mobile search is considered the next major internet growth market.
Mobile phones already outship PCs by a wide margin, while high speed data services are gaining in popularity. Devices such as Apple's upcoming iPhone are also making it easier to navigate the mobile web.
Most mobile web browsing is limited to pages that are offered directly by mobile operators.
But as users get more comfortable with browsing the web on mobile devices, they are expected to embrace search in the same way that they did on regular computers.
The mobile search market today is dominated by so-called white label search providers that allow operators to offer their own search engine. Microsoft acquired a major player in that field through the purchase of MotionBridge in 2006.
Google launched a mobile search engine in 2005. While it favours pages written in extensible HTML optimised for mobile internet users when it ranks search results, it does not interpret queries like Yahoo.
Yahoo is aiming its service squarely against Google's. The company has published a PDF that highlights the differences between the two services.
Mobile phone users can access the service by surfing to http://m.yahoo.com on their mobile device.