[wolfrom]

We actually have that very tool developed (alpha-ish, I guess you'd say), but we found that no one seemed to pay much attention when we talked about it. That, plus the difficulty in monetizing has put it on hold in favor of the Windsoc API.

The Windsoc Social Client aggregates activities and includes the concepts of Circles and Channels. Circles are collections of people just as you described, actually, while Channels work to split contacts and services (and someday individual activities) into separate subject areas. This is because usually I'm on startup mode, but when I'm relaxing I like to change over to my other interests.