Jeffrey Heer, student in Information Visualization and Presentation, is working on Vizster, an interactive visualization tool for online social networks, allowing exploration of the community structure of services such as friendster, tribe, and orkut.
With this tool, social networks are illustrated as images with nodes (circles or squares) for each person linked via connectors (lines) showing relationships.
Some academics and hackers had already thought of this kind of visualization, Friendster even put a mockup of it on their front page, but they never implemented it seriously.
Besides, Vizster features a comparison mode, with direct visualization of various profile attributes (such as number of friends, age, gender, relationship status, last login date, etc.)
Found in Cheesebikini.