"You probably have already heard about Feedster, but in just in case you haven't here's a little story for you. The best tool I use for following topics discussed in blogs is Feedster, the Google for blogs. When Microsoft XNA was announced, I thought I'd like to "listen" to the ensuing discussion and watch for links to information on XNA. I searched for XNA on Feedster and then subscribed to the search. Now I get a custom aggregated RSS feed of blogs, forums and news sites discussing my topic of choice. That's pretty powerful stuff, and one of the best uses of RSS aggregation to date.
Now you may be familiar with other sites that are similiar like PubSub. Why Feedster over others? There are no subscriptions, no email collecting, nothing strongly organized; just an open, easy search. Another reason I like Feedster, they run a blog and they sign their names to each entry. It appears that most of them have ther own blogs up and running too. And I can look them up in Orkut and see their little faces on my computer screen. What value does that add? Accountability, transperancy and they're in the blogging community. Go Feedster!"