In what has become an annual Silicon Valley ritual, leading venture capitalists have made their predictions about which technologies will thrive and which will take a dive in the near future.

The fact that they don't all agree made for some lively discussion Tuesday at an event in California, U.S., called the Top 10 Tech Trends Debate. The ninth annual event, which drew 800 people to a hotel ballroom dinner, was hosted by the Churchill Club, a public affairs forum.

The iPhone will be a hit, but not world changing. The hot Web 2.0 market will cool, or it may keep bubbling. There wasn't always consensus.

The coming iPhone from Apple, a combination cell phone, music or video player and Web device, is going to be popular but there is some debate about whether it will dominate the mobile market or just help sales of all device makers.

"It's going to stimulate the mobile device market and require more belt space," said Roger McNamee, cofounder and partner of Integral Capital Partners. "I don't see iPhone as a substitute for all phones, but as a substitute for the iPod," said McNamee, of Apple's non-phone digital music player.

While competitors may respond with iPhone-like products of their own, it's unlikely there will be a complete market shift to a converged device, said Steve Jurvetson, managing director of Draper Fisher Jurvetson. "People do not need all their devices all the time."

But iPhone's impact should be significant, said Joe Schoendorf, a partner with Accel Partners. He cited news reports that AT&T Inc., the exclusive wireless service provider for iPhone in the U.S., has received 1 million requests for iPhones in advance of its June launch.

The Web 2.0 phenomenon, the proliferation of Web sites based on user-generated content, is so hot it is bound for a correction, said Tony Perkins, a Silicon Valley author and publisher who moderated the debate. He sees a "Web 2.0 shakeout," based on his belief that Google paid too much when it spent US$1.65 billion for You Tube in 2006. Perkins forecasts VC funding "down rounds," in which Web 2.0 companies receive less money in a subsequent funding round than they did in previous rounds, as evidence the market is saturated.

But talk of a Web 2.0 shakeout is premature, said John Doerr, a partner in Kleiner Perkins Caufield & Byers, the legendary VC firm that funded such successes as Google, Amazon.com and Sun Microsystems.

The venture capital industry funded 167 Web 2.0-related deals in 2006 for a total of $844 million, mostly in Europe and the U.S., according to a March 21 report from the accounting firm Ernst & Young and Dow Jones VentureOne. That's more than twice as much money and nearly twice as many deals as in 2005.

"I don't see that slowing down," Doerr said.

In fact, the enterprise space is as yet uncharted territory for Web 2.0-type applications, said McNamee. Companies can create their own Web 2.0-like sites for collaboration on company projects. Consumers can also use them for sharing advice on personal finance.

"We need Web 2.0 applications that really move people's lives," he said.

Other predictions debated by the VCs ranged from green technology to the movement of media content and ad revenue online to advancements in biotechnology.