Using the Digg API, Brian Shaler created a map of Digg users and how they're connected to each other. On the map, users are organized by the length of time they have had accounts on Digg. The oldest accounts are at the center and accounts created in the last few months are around the edges. The map only includes users who utilize Digg's friendship feature.
The map has some basic interactive functionalities by allowing you to click anywhere on the map and type a Digg user name to see where on the map that user is located. Besides the location on the map you can also know the number of friends and fans that particular Digg user has.
As acknowledged by the author, this Digg friendship map is not a practical analysis tool, but nonetheless, it's an idea that has been in his head for quite some time and he just decided to implement it as a visualization piece.
Note: Click on "Show Time" on the map to better understand the visualized time span.