Basically TailRank is a memetracker, it is also a personal memetracker like megite…enter your OPML and find the hot news from these feeds, it will all cluster similar/related items from the rest of the blogosphere.
A new feature is to memetrack just one feed or post:
Enter a URL of a blog eg. TechCrunch, and you will see that each TechCrunch post has a cluster of similar/related posts from the blogosphere…and you can also track a single post (thread) by RSS or IM.
At the moment I’m using Sphere to find related posts to my blog, but TailRank is much more, because it gives some sort of thread and context feel.
See the blog post for the latest additions.