Here is the article that I read recently about Web 2.0:
PS Here is the Best Web 2.0 software of 2006:
Among the best Web2.0 software, I highly recommend you to try to use StumbleUpon.
This software collects the good web site in the related field (e.g. computer, music, graphic designing ant etc ) recommended by the StumbleUpon user.
For my experience, I usually found a very good web site in the related topic by StumbleUpon.
I even feel that the site is better than you search in Google.