Looking at what said Tim Berners-Lee on Web 2.0: "nobody even knows what it means". There is an interesting article relating this story at http://arstechnica.com/news.ars/post/20060901-7650.html
which has been written by Nate Anderson.

Let me quote what TBL said "When asked if it's fair to say that the difference between the two might be fairly described as "Web 1.0 is about connecting computers, while Web 2.0 is about connecting people," Berners-Lee replied, "Totally not. Web 1.0 was all about connecting people. It was an interactive space, and I think Web 2.0 is of course a piece of jargon, nobody even knows what it means. If Web 2.0 for you is blogs and wikis, then that is people to people. But that was what the Web was supposed to be all along. And in fact, you know, this 'Web 2.0,' it means using the standards which have been produced by all these people working on Web 1.0."

It seems there is a lack of a real definition and consistency about web 2.0 which at the end looks like a pure marketing operation. Anyway, what seems to be interesting to me is that we are at the corner about connecting people and about connecting concepts (semantic web) which explains why I decided to focus my research activity on "people-concepts" networking.
for more information about "people-concepts" networking just go there:
http://www.ami-communities.eu/wiki/Knowledge_Connection_Working_Group