Google Inc. first gained notice early in the decade, as a small and quirky start-up with a disarmingly simple Internet search engine and an idealistic slogan, ``Don't Be Evil."

Today the maverick company, adored by online shoppers and Internet surfers, has emerged as one of the most disruptive forces in the business world. Its secret sauce: a technology that lets business customers link targeted ads to search results and Web content.

By rolling out a spate of free search products, from Google Maps to Google News to Google Calendar, the company is doing more than building its consumer base. It's also building an alternative environment for software, advertising, and Internet content that is challenging the business models and eroding the revenue of everyone from publishers to software makers to Internet service providers.

"Google is causing disruption in a variety of areas," said Anthea Stratigos , co founder and chief executive of Outsell Inc., a Burlingame, Calif., research firm. "It's pushing advertising revenue online. It's creating a model where software can be hosted by ad funding. Because of Google, things that have long been fee-based now have the potential to be free to consumers and supported by ads."

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