Just reading the JISC Tech Watch report: What is Web 2.0? Ideas, technologies and implications for education by Paul Anderton. It is available at http://www.jisc.ac.uk/whatwedo/services/services_techwatch/techwatch/techwatch_ic_reports2005_published.aspx
It contains some useful descriptions of new services/technologies, raises the issue of whether this is a new phase of the web or not and highlights some interesting issues (the big 6) behind Web 2.0:
1 Individual production and User Generated Content
2 Harnessing the power of the crowd
3 Data on an epic scale
4 Architecture of Participation
5 Network effects, power laws and the Long Tail
Definitely worth a read to feed into our learning curve about this area of development.