This is an interesting and somewhat useful article about Web 3.0. It describes what many would agree the elusive Web 2.0 term means. (If you feel like you've never been completely sure exactly what Web 2.0 means, you're not alone. It's an ill-defined term).
This article probably falls short, though, on it's predictions. I'd say almost the majority of what it predicts is already here in some form, not something out in the future.