Locality is inherent to the value of craigslist; I go to craigslist.org but I get kicked over to the local instance of craigslist (my IP address sources me to somewhere in the illustrious Lansing, MI). But how does craigslist know where to send me? Some mysterious system of assigning a geocoded IP address to just the right site must be in place...I wonder what that map looks like.
When Ian Clemens proposed the idea, I looked around to find an existing map of craigslist sites-to-areas -maybe even find the lookup that they themselves use. I couldn't find anything like it.
Whether it matches their system well or not, here is a map that approximates geographic coverage to individual sites using a Voronoi process as a base (more info on process below). It is at least a start at visualizing the geographic coverage and distribution of the community-driven instances of craigslist. Shapes like this might provide some useful context for other data, demographic or market information, for instance. Also, when pulled into VFX, it can serve as an input to some spatial querying on those other metrics.
This and other ginormous map prints available at www.zazzle.com/idvswag