Nov. 1--It's a global battle whose foot soldiers will be engineering teams working inside a few square miles of Sunnyvale and Mountain View, with billions of dollars in advertising at stake.

Almost a decade after Google became a household name, Microsoft's launch of its Bing search engine, followed by Microsoft and Yahoo's deal to collaborate on search, could give the world's dominant Internet search engine its first serious challenge in years, as search becomes a key front in the looming competition between Google and Microsoft.

But regardless of who wins this competition, the beneficiaries are everyone who uses search engines, as quickening innovation improves the quality of information and delivers it in more useful packets. This year for the first time, a majority of the roughly 180 million U.S. adult Internet users typed a query into a search engine on a typical day, and search is gaining on e-mail as the most common online task.

Thanks to new technology, users will get their answers faster, from more than just text, and if the companies are successful, may find search engines are better at understanding what they are looking for.

"Search is going to change more in the next year than it has in the past five years," said Ben Schachter, an analyst with Broadpoint AmTech, who believes the pace of search innovation is the greatest in at least a decade.

Deluge of innovation

The pace of new features

rolled out by Google, Yahoo and Microsoft has been furious in recent weeks.

At the Oct. 20-22 Web 2.0 industry conference in San Francisco, Microsoft announced a deal that allows Bing to search up-to-the-minute postings on Twitter, with much of the software engineering done at Microsoft's Mountain View campus. Google scrambled to announce its own real-time search deal with Twitter several hours later.

Not to be outdone, Google last week unveiled a new service that allows people to search for a specific song title and see a link to that song on MySpace or Lala in their search results -- a service Google described as yet another way to speed users to results.

Within minutes of Google's music launch, Yahoo posted a company blog reminding that its search engine has had the ability to show links to free audio files in a partnership with Rhapsody since 2008.

Google has been unveiling so many search changes -- even tweaking the size of the search box on its sacrosanct home page and pinching advertising on the results page slightly toward its center-- that it has begun a "This Week in Search" item on its company blog to track new features.