Yahoo is hoping to leapfrog Microsoft by releasing a tool that allows users to quickly and easily search for information on their PCs as well as in their personal files stored at Yahoo's online services, a source familiar with the plan said Wednesday.Yahoo\u00a0is hoping to leapfrog\u00a0Microsoft\u00a0by releasing a tool that allows users to quickly and easily search for information on their PCs as well as in their personal files stored at Yahoo's online services, a source familiar with the plan said Wednesday.Microsoft\u00a0previewed an upcoming desktop search application\u00a0last week at an event for financial analysts at its Redmond, Wash., headquarters. The tool builds an index of content on a user's computer and makes it searchable. Relevant links from the Internet, along with advertisements, are displayed in a pane on the right side of the screen.Yahoo is developing a similar tool but plans to take its capabilities a step further, according to a person familiar with the plan. In addition to letting users search their local mail and hard drive, Yahoo's tool will extend the search to include personal files stored at its online services, such as e-mail, calendar, and picture hosting, the person said.Among the key benefits of such tools is that users should be able to search through files on their desktops much faster and more thoroughly than they can with the search feature currently in Windows. "The search available in most operating systems is impoverished," said Matthew Berk, an independent analyst based in New York.Microsoft did not provide a release date for its desktop search application last week, but on Wednesday, MSN Product Manager Justin Osmer said the tool would be out in the first half of 2005. A new version of its MSN Web search engine is due out at about the same time, he said.Yahoo officials declined to comment on any plans for a desktop search tool, but Jeff Weiner, Yahoo senior vice president for search and marketplace, said users should "stay tuned."Microsoft and Yahoo aren't the only companies focused on searching the desktop. Lycos released its HotBot Desktop tool earlier this year, and Ask Jeeves acquired a desktop search technology in June from Tukaroo. Google is also rumored to be working on a product.Additionally, a host of third parties provide tools. One of those, Lookout Software, was recently acquired by Microsoft.The interest in desktop search is not surprising, said industry analyst Berk. "Operators of Web search want to get on the desktop because it gives them more opportunity to display ads," he said. "The more you get consumers to search through your technology or service, the greater your opportunity to drive revenue."