TraceEncounters is a social network tracking and visualization project. It was debuted September 3 in Linz, Austria at the 2004 Ars Electronica festival. White circles connect cliques of size greater than 3 when the user clicks the 'Find cliques' button.
The brighter links mean more encounters between the two people involved, and they're also the strongest springs, so it's possible to extract cliques by pulling out one or more of the people involved in the clique. (Often the greenest ones - the people having the most connections to other people regardless of the number of conversations - are the best to pull on; they're intentionally the easiest to pick when several nodes are nearby.
The project distributed aproximately 900 small stickpins, each of which uses limited-rage infrared data exchange to remember every other pin that it encounters. When pin wearers came to a central location to view the accreting network, they saw a thousand circles on a plasma display panel, each representing a pin.