whats 2.0 ?

lately I find myself using X 2.0 quite frequently... we're facing philosophy 2.0, the world is in its second review. the concept of God needs a 2.0...
yesterday I read what Tim o'reilly thinks is 2.0:

http://radar.oreilly.com/archives/2007/05/what_would_goog.html

Tim says it all depends on "the way these companies act with regard to the data they collect". 2.0 web services "mines its database in real time and builds the results right into its customer-facing applications" using some heuristics on this mined data, they achieve a far greater user experience. He also says its something about 'liveness' of the thing.

a Blonde 2.0, OTOH, thinks 2.0 is "a better and more effective way for us to act upon the same human needs that we’ve always had such as connecting, communicating, and receiving feedback from others" (http://www.blonde2dot0.com/blog/2007/09/27/the-death-of-web-20-cmon/)

2 faces of the 2.0: better understanding of the data collected, and better processing by the power of many to offer better user experiences.

I dont have an opinion, myself. Well, I guess I might have one, but dont regard it very relevant.

(UPDATE:)
well, putting it another way, I think the 2.0 is a marketing/social/business thing. I am an engineer, so I dont give much credit to these 'trends'. I remember talking to my partners about a web page, they kept saying 'yes, you do this in ajax', I didn't get the whole sense of what they meant, and I kept saying 'you mean XMLHttpRequest ?', so for me there's no AJAX thing, theres XMLHttpRequest, and there's no 2.0 thing, there's a bunch of new aproaches to web interfaces, application architecture, and yes, also a new way of doing web sites where the user is also the producer: a more social approach.
Amongst other reasons, I didnt get ajax because I was doing a firefox extension, so I had studied the APIs firefox provides, I didn't learn jQuery or prototype, where there's more a sense of 'AJAX'. Well, actually I did understood what they meant, but wanted to remain as much engineer and as least 'marketinian' as I could.
Hype makes economic bubbles, engineering never did any harm, it only delivers (hopefully)good technology.

regards