This is a "mention map" of people and hashtags that I mention on Twitter. You can get your own embed code.
Asterisq is a local Vancouver company that is doing really interesting things with data visualization. Data visualization is an increasingly hot area, going from "neat!" to "wow, I would never have had this insight without seeing it like this".
The guys at Asterisq are looking for big data sets and partners to work with, so contact them if this sounds interesting. They've got a gallery of some other custom implementations of graphs. Bonus points for Drupal integration and also some Facebook integration.