See Something or Say Something is a project by Eric Fischer which maps out locations of Flickr pictures (red dots) and locations of Twitter tweets (blue dots). Note the white dots are locations that have been posted to both services. Although there are no conclusions and none intended, it does raise some interesting questions about what makes us take a photo rather than post a tweet, and vice versa. The software that creates the maps is a C program that runs through the photos/tweets in chronological order, plotting the earliest ones the most brightly and stepping the brightness down for points that don’t show up for the first time until later on. There is no user interface — it just takes (from the command line) coordinates of the corners and a data file of locations and writes out a JPEG. Points are also allowed to diffuse by a few pixels when there is an additional record for a point that is already plotted, with the brightness falling off exponentially as the point that is actually plotted gets further from its intended location. Each pixel is 2.25 square miles as a smaller area made the world image too big for Flickr.