The three started Powerset, a company whose aim is to deliver better answers than any other search engine— including Google—by letting users type questions in plain English. And they have made believers of Silicon Valley investors whose fortunes turn on identifying the next big thing.

“There’s definitely a segment of the market that thinks we are crazy,” said Charles Moldow, a partner at Foundation Capital, a venture capital firm that is Powerset’s principal financial backer. “In 2000, some people thought Google was crazy.”

Powerset is hardly alone. Even as Google continues to outmaneuver its main search rivals, Yahoo, plenty of newcomers— with names like hakia and ChaCha— are trying to beat the company at its own game. And Wikia Inc, a company started by a founder of Wikipedia, plans to develop a search engine that, like the popular Web-based encyclopedia, would be built by a community of programmers and users.

These ambitious quests reflect the renewed optimism sweeping technology centers like Silicon Valley and fuelling a nascent Internet boom. It also shows how much the new Internet economy resembles a planetary system where everything and everyone orbits around search in general, and around Google in particular.

Silicon Valley is filled with start-ups whose main business proposition is to be bought by Google, or for that matter by Yahoo or Microsoft. Countless other start-ups rely on Google as their primary driver of traffic or on Google’s powerful advertising system as their primary source of income. Virtually all new companies compete with Google for scarce engineering talent. And divining Google’s next move has become a fixation for scores of technology blogs and a favourite parlour game among technology investors.

It may not be the last great business model, but Google has proved that search linked to advertising is a very large and lucrative business, and everyone— including Ms Dyson, who invested a small sum in Powerset— seems to want a piece of it.

Since the beginning of 2004, venture capitalists have put nearly $350 million into no fewer than 79 start-ups that had something to do with Internet search, according to the National Venture Capital Association, an industry group.

In some ways, the willingness of so many to make multimillion-dollar investments to take on Google and other search companies represents a startling change. In the late 1990s, when Microsoft dominated the technology world, inventors and investors did everything they could to avoid competing with the software company.

Yet many of today’s search start-ups say that Google’s dominance today is different from Microsoft’s in the late 90s when its operating system was a virtual monopoly and nearly impossible to break. In the Internet search industry, “you earn your right to be in business every day, page view after page view, click after click,” said Barney Pell, a founder and the chief executive of Powerset, whose search service is not yet available.

But at the same time, Google, Yahoo and Microsoft have thousands of engineers, including some of the world’s top search specialists, working on improving their search results. And they have spent billions building vast computer networks so they can respond instantly to the endless stream of queries from around the world.

Ms. Dyson, the technology commentator and Powerset investor, captured the optimism more concisely and with less swagger. “I love Google,” she said, “but I love the march of history.”

-MIGUEL HELFT