At the Seoul Digital Forum in May Eric Schmidt (Google) was asked to define Web 3.0.

"My prediction is that Web 3.0 will be seen as applications with
a number of characteristics. They are small, the data lives in in a
cloud, applications will run on any device – PC or mobile, applications
are fast and customisable, distributed virally through social networks
and email…

"That’s a very different application model than we’ve ever
seen in computing – very different from the mainframe era, the PC
industry and likely to be very, very large."