What is "Web 2.0"?

When Olly and I met up with the Soos for a curry, his brother PS was there...playing the X-Box 360. We got into a blether about blogs and flickr and PS used the term "web 2.0" to describe what we were doing. I have been doing some digging (well actually I did one google search... but hey, it took a lot of effort to do!) and found a fab article by Tim O'Reilly that describes "web 2.0" - heres a diagram that shows the way our thoughts are changing:

Web 1.0 --> Web 2.0
DoubleClick --> Google AdSense
Ofoto --> Flickr
Akamai --> BitTorrent
mp3.com --> Napster
Britannica Online --> Wikipedia
personal websites --> blogging
evite --> upcoming.org and EVDB
domain name speculation --> search engine optimization
page views --> cost per click
screen scraping --> web services
publishing --> participation
content management systems --> wikis
directories (taxonomy) --> tagging ("folksonomy")
stickiness --> syndication

Check it out... THe article is fab and describes the paradigm shift that we are on but maybe weren't quite aware of. Link

oh and it was a great curry! and PS rules the X-Box 360 (The only Doctor I know who does!!!)