I'm beginning to think that web 2.0 doesn't really indicate 2nd generation but rather the new aggressively 2-way nature of the web. Case in point, this years edition of Reboot. It seems the social momentum of blogging (and a grassrootsy turn of the program, maybe) has changed the dynamic of the conference from wanting to be an audience drive event to actually being one. It is in fact almost as if the audience has taken over, which I'm sure is very much the idea. The conference home page is a wiki - and none of the pages are edit locked. There's already a reboot podcast and this was not put together by the organisers. A number of reboot related semi-official and unofficial events are popping up before and after the conference
In contrast the 2-way approach wasn't tried 4 years ago and at least partially failed 2 years ago.