Tailrank is developing nicely.
Kevin Burton is doing a great job at speedily developing the service and seems to be increasingly getting the attention it deserves. In TechCrunch's latest review of Tailrank, Michael Arrington points out a feature I think we will see more of in the aggregator space: the clustering / threading of blogs posts and items to help the navigation of discussions taking place.
This threading was one of the five 'requirements' I described to help me find the signal in the noise. For me at least, it is precisely this threading feature helped Memeorandum stand out from the crowd. One bit of feedback for Kevin I have (and have given) is that I'd like to see more items on the thread, currently the max is two (no doubt this a UI design decision to keep things as clean as possible, but it would be nice if the user could define this threshold).
The other requirement I had was the ability to import / reference my OPML file (RSS subscriptions). Tailrank did this. The feature has gone (for the moment). The idea is it allows all of Tailrank's functionality and algorithms to pivot on my personal A-list of bloggers, news sites and sources. By allowing me to define what and who I want to pay attention to, the service's relevancy hits a high mark, instantly. I spoke (IM'd actually) with Kevin tonight and there is some cool stuff he's brewing in this area...he's letting me beta test his stuff under wraps...good stuff as far as I can tell.