What is Web 2.0

Just came across Web 2.0 conference in greg linden's blog. What is web 2.0 ? a new version of the internet :)).. How can the internet have a version.. Is is just a marketing hype?

The need to have this versioning comes from the fact that the business models/ technology on the web are changing.. The web is becoming user driven.. user generated content [Wikipedia], user centred content, content recommended for the user [Findory], user collaboration.. and the list goes on..

Oreilly has a nice article on this.

Here they mention the changing scenarion by example

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