My fav techie blog is techcrunch, and here they do a good summary of the leading web2.0 apps:

http://www.techcrunch.com/2008/01/01/2008-web-20-companies-i-couldnt-live-without/#more-12529

An excellent article from wired on the music business by David Byrne, is:

http://www.wired.com/entertainment/music/magazine/16-01/ff_byrne?currentPage=all

Isn't funny that the avant garde artists like Bryne, Gabriel (http://www.petergabriel.com/), and Radiohead understand the business far better than the executive$