Jason Calacanis just defined web 3.0 for everyone. However, read the comments and you'll find that a lot of people disagree.
Everyone talks about how Web 1.0 was about machines and Web 2.0 is about user-generated content, but I have a different way of looking at it. Didn't Web 2.0 happen because a market crash ended Web 1.0? How can we define Web 3.0 without a second crash? Maybe all this Web 3.0 stuff is all part of 2.0, and 3.0 will be about something entirely different.
I still find it amazing how, throughout this entire discussion, no one has mentioned money, economics, profitability, or anything even remotely related to actual business.