Now in its fifth year, Web 2.0 Summit will focus this time on using the Web to tackle major challenges in areas such as health care, climate change, politics and finance, according to event producers O'Reilly Media and TechWeb.

CEOs including Yahoo's Jerry Yang, Facebook's Mark Zuckerberg, Intel's Paul Otellini and MySpace's Chris DeWolfe will also participate in the conference, which runs from Wednesday to Friday in San Francisco.

Web 2.0 innovations such as blogs, wikis, social networks and syndicated feeds have hit the consumer and workplace mainstream, becoming an integral part of many people's daily lives, so it's natural to attempt to use them to tackle big problems, said industry analyst Charlene Li.

"Web 2.0 isn't just an isolated technology. Web 2.0 changes relationships and the way people communicate, and because of that, it also changes the way we approach problem-solving, too," said Li, founder of , a provider of speaking and consulting services around emerging and social technologies.

Because a common thread in Web 2.0 is harnessing the wisdom of crowds and promoting widespread collaboration, these technologies and services lend themselves naturally to addressing large, complex problems that defy simple solutions, she said.