John Battelle (via Toni) seems to think along the same lines, and to have been prodded to commit his thoughts to paper, or at least to presentation and to pixels. Here’s his slide comparing core values of Web 2.0 from way back in 2004/5 with today’s web and with today’s apps.
When it comes to apps’ popularity, the bottom line is rich user experience. Apps’ UX lead is “so compelling we may be willing to give up all the other principles of Web 2 just to have a great experience.” Who’s this we? Well, it may include me once I get my iPad 2… but I doubt it.