I found a link to Nexus in my reader this morning thanks to a post from Information Aesthetics, and decided to check it out. It's an app for Facebook that graphs out a member's network, indicating connections and clusters. Here's my network:
Moving the mouse over any dot within the Nexus app highlights that person, and their connections. It's pretty easy to see things like the University of Calgary folks (the lines of dots in the middle), the Northern Voice folks (on the left side, mostly), family members and old high school friends (the unconnected mini-networks outside the main circle).
It's an interesting application, but is restricted to just the "friends" you've made in Facebook. I'd love to see something that takes this and adds the Google connections from TouchGraph, my network in del.icio.us, contacts on Flickr, subscriptions in Google Reader, etc... Tie that in with some kind of meaningful online identity system like OpenID, and we'll start to see some pretty meaningful ways to organize and navigate our online networks.