The March/April issue ofTechnology Review has an interesting piece on visualizing social networks (via Matt Hurst). All of the examples would make appropriately geeky wall charts or desktop backgrounds, but the one that caught my eye is the one that adds color to a social network chart to illustrate comment activity.
Offenhuber and Donath created these images by tracking where and how often users left comments for other users; connections are based on these patterns, rather than on whether people have named each other as "friends." As the time since the last communication grows, the visual connection begins to fade.You'll want to go through the whole article. In addition to an application idea for the Comment Flow visualization, the article has examples of visualizations based on blog links, Twitter, social networks in the enterprise and viral marketing.
Nice of 'em to point out some of the researchers working on this stuff, isn't it?