Danny Sullivan suggests that a weakness of memetrackers is how they let big stories crowd out everything else. I ran into this same thing yesterday when I noticed that the "personal memetracker" I'm working on for FeedDemon was filled with stories about the Rocketboom dustup.
Gabe Rivera intends to make some refinements to Techmeme's design because of this issue, but he clearly understands that this could get tricky since some users will always want to see the entire cluster of stories related to a topic.
One option (which is admittedly easier on the client side than the server side) is to simply enable the user to hide a specific topic. I like this idea because users are way smarter than their software when it comes to figuring out what they like. So, this is what I've decided to do in FeedDemon - you simply have to click an icon to remove a topic [screenshot].
(via Rex Hammock)