Randall "XKCD" Munroe has updated his legendary "Online Communities" map. Drawing from diverse data-sources, he's laid out a notional map of a world where geographical scale is determined by the size/intensity of community engagement. Filled with tons of sly humor and tiny details, it's a worthy successor to the original. I hope he does a poster of this one, too!
Update: Randall Munroe sez, "you may have missed the link at the top of the page — I've actually got the poster up for preorder already. I did this one preemptively."