This image graphs the paths of 553 Twitter users in Singapore and is still a work in progress. Each segment shows a journey taken by one Singaporean from one point to another on the island, and the chart shows over 5000 journeys. In effect, I like to think of this graph as the paths of movement of the average Singaporean.
The big blob you see at the bottom is downtown, while Changi airport is to the extreme right (where all the international flights are). I am eventually going to put up an interactive tool where you can narrow down paths by time, destination, and origin.
Here is another image mapping out the location of all the tweeters in Singapore from 4 to 4:30PM on March 25, 2011. This one is live on my tool The View From Above.
All rendering done on Chrome within the HTML5 Canvas element using processing.js
Lastly, here is a Google Map for comparison.