David Rothman announces LibWorm:
http://davidrothman.net/2006/11/25/libworm-search-and-current-awareness-for-libraryfolk/
With LibWorm, you can search over 1100 feeds, including more than 800 biblioblogs, many LIS journal TOCs, and many other information sources of interest to libraryfolk.
Any search in LibWorm can be outputted as an RSS feed, so LibWorm should be a very useful way to track mentions of your favorite subjects in the biblioblogosphere and beyond.
You can choose to use LibWorm’s built-in aggregator by registering for an account, and this will also facilitate the social aspects of the site that will be implemented in the future.
Check out the feed categories, including podcasts form various types of libraries and a feed labeled “Meta.”