[Air-L] Web 2.0

Hi everyone, I`m doing a research about the influence of web 2.0 in participation (or e-participation). At this moment I`m interested in the web 2.0 definition and web 3.0 definition. Can anyone recommend some must-read articles about web 2.0/web 3.0? Thank you Maria Manuel (PhD student at University of Minho, Portugal)