If you're into social software, webfeeds, aggregation and so on, you really should be keeping an eye on Bloglines, the premier Web based feed aggregator. They recently redesigned and made an effective Web interface even more usable. Just rolled the dang thing out, and everybody benefits.
Bloglines also added "clip blogging". You see an item in a feed you like, you click a button, it goes into a blog. Big deal you say, plenty of of aggregators can do something similar. Yeah, but they're not holding the data for tens of thousands of people. And since Bloglines owns the interface, if clip blogging takes off, they can start adding fun stuff like group clip blogs. I worked on a paper submission last year (rejected, wah) which posited on some interesting UI stuff that could be done in such an environment. The problem is getting enough people together to run a decent experiment. Well there's at least one place it could be done.
Bloglines: the Google of aggregation?