Libworm is a site I discovered through delicious. It is a search engine for library blogs. Here is what they have to say about themselves.
Frankie Dolan, a UK-based IT engineer, built the infrastructure for MedWorm.com. David Rothman, a medical library paraprofessional and blogger in Syracuse, NY, suggested to Frankie that this infrastructure would also work very well for making the biblioblogosphere more searchable. Frankie liked the idea, and said she was game if David would take on the day-to-day administrative tasks. David collected the feeds, applied categories, proposed some pre-set searches, and made suggestions about functionality and interface design; Frankie built everything that makes LibWorm work.
It is a wonderful site. I used it to search for North Texas Regional Library System and it showed me all of our blog postings and any other blog that mentioned us. Sweet! I then added the search to my My Yahoo news page so I can monitor the biblioblogosphere for any mention of us.
I think the tool would be especially helpful for newcomers to the biblioblogosphere. You can monitor your favorite feeds with it and even store articles on your account. You can easily create an account and they make a point of mentioning that the service is free.
If you need to find out what they are saying about a hot library topic in the biblioblogosphere, this would be the first place I would go.