Attendance at the 2008 Health 2.0 Conference doubled from that of last year's nearly 500, underscoring the evolution and growth of search, social networking and tools for individual and group consumer use, says its co-founder.

"Health 2.0 is here in the mainstream," Matthew Holt said in his introduction, on Wednesday, the opening day of the conference.

Co-founder Indu Subaiya said that Health 2.0 is exploding and broadening its reach to include wellness, gaming and genomics.

In his keynote address, Clay Shirky, author of Here Comes Everybody, which discusses the use of technology to organize without organizations, said that the most valuable thing about the Internet is its ability to connect people and provide group access for collaboration.

There is "enormous demand" for Health 2.0's ability to provide a trusted online information center and to enable collaboration and cooperation within that information center, he said. "Wherever people decide to trust each other, the information will flow," he said.

In this arena, the ability of individuals to pool resources creates new values, he said.