Somewhere deep down in my rational brain, I knew the hole wasn't real - that it was a virtual reality scenario in a cramped office at Stanford University, where the floor seemed completely pit-free until I put on a clunky piece of hardware called a "headmount." But that headmount changed everything.

"Increasingly the Internet itself, given our reliance on it, is a source of destructive technology. I think we really have to worry about cyber terrorism and cyber crime increasingly. But there's obviously nuclear proliferation and bio-weapons and chemical weapons."

"I think it's had two diametrically opposed effects. One effect has been really good. It's created transformation and empowered people and allowed us to debunk bad ideas in a very ... decisive way. It's almost created a cognitive immune system for the planet."

He continued: "It's also empowered pranks and pseudoscience and bad information because every person on the Internet can sort of find the people like them and everyone can find an audience so there are certain forms of ignorance that would more or less be unthinkable without the Internet. Global jihad has been massively empowered by the Internet. Even things like the 911 truth conspiracy. That, to my mind, is an Internet phenomenon. No one would publish those books. This is something that is born of Web sites and Internet commentary."