Hype Machine [1] is a blog that aggregates music blogs and automatically generates playlists and let's you "spy" on what other people are doing on the blog.
Links:
[1] http://hypem.com
[2] http://hypem.com/radio/?w=1
[3] http://hypem.com/badge?bc=radio/now&w=1
[4] http://felix.openflows.com/taxonomy/term/12