I spent some time playing with Feedster last night. There are some very, very cool things going on over there. The ones that really grabbed me were:
- Filtering searches to include only your blog, only your blog and other blogs in your OPML file, or excluding your blog.
- Being able to subscribe to an RSS feed of search results, ordered by date.
The filtered searches are even cooler because they can be launched from your own site. Here is an example:
Search my blog and other blogs I read:
Search Feedster excluding my blog from the results:
This link shows a historical list of all my blog entries:
Powered by: 
So this searching stuff is really cool, but what takes it to another level is the RSS feed that is available for search results. You can use this to monitor blog chatter on any topic you want via RSS. For example, I’ve subscribed to an RSS feed of search results for "alex king" – now whenever someone mentions me in their blog, it will show up in that RSS feed.
You can create a custom RSS feed for any topic you want! This is very, very cool. Hats off to Scott Johnson for making some very powerful tools. (Scott is also a user and fan of tasks 🙂 )